Search

Light-emitting diode phototherapy treatment for jaundice of the preterm infant presents adverse effects, such as discomfort, changes in metabolism, and overheating. This study quantified the body heat exchanges between the environment and a simulated preterm infant requiring phototherapy treatment in a closed incubator. Phototherapy treatment increased the mean incubator roof temperature by 2.9 °C (p 0.001) and the incubator air temperature by 1 °C (p 0.001). Analytical calorimetry was used to calculate the additional energy received during phototherapy and thus deduce the optimal incubator air temperature for ensuring thermoneutrality and preventing hyperthermia. The optimal air temperature settings inside the incubator during phototherapy were - 0.51 to - 1.25 °C lower than references, for preterm infant weighing 500 to 2000 g.Conclusion: Phototherapy treatment for jaundice of the preterm infant increased the incubator air temperature. To prevent overheating in the preterm during phototherapy, new curves for optimal air temperature settings inside the incubator were calculated with analytic calorimetry. What is Known •Phototherapy treatment is the first-line treatment for jaundice in the preterm infant. •Phototherapy treatment increases the risk of overheating. What is New •The heat transfers and risk of overheating were quantified using a thermal manikin during phototherapy treatment. •Phototherapy treatment increased the incubator roof temperature and heat transfers. •New incubator's air temperature settings during phototherapy treatment were calculated with analytical calorimetry for preterm infant weighing 500-2000 g.

Aim Frequent nursing procedures can modify a newborn infant's thermal environment when their incubator is opened. This study evaluated the impact of relative humidity on preterm infants in closed incubators and calculated their heat loss and additional metabolic cost. Methods We studied 45 preterm infants born before 32+0 weeks, nursed at the neonatal intensive care unit at Amiens University Hospital, France from January 2009 to November 2011. Their body, skin and air temperatures and the incubator's relative humidity were continuously recorded from days 1-8 of life and the differences between the measured and target relative humidity were calculated. Body heat loss was also calculated. Results On day one, the measured relative humidity (68.7 ±1.0%) was significantly lower than the target relative humidity (75%, p

Low-birth-weight (LBW) neonates are nursed in closed incubators to prevent transcutaneous water loss. The RH's impact on the optimal incubator air temperature setting has not been studied.On the basis of a clinical cohort study, we modelled all the ambient parameters influencing body heat losses and gains. The algorithm quantifies the change in RH on the air temperature, to maintain optimal thermal conditions in the incubator.Twenty-three neonates (gestational age (GA): 30.0 [28.9-31.6] weeks) were included. A 20% increase and a 20% decrease in the RH induced a change in air temperature of between -1.51 and +1.85°C for a simulated 650g neonate (GA: 26 weeks), between -1.66 and +1.87°C for a 1000g neonate (GA: 31 weeks), and between -1.77 and +1.97°C for a 2000g neonate (GA: 33 weeks) (p0.001). According to regression analyses, the optimal incubator air temperature=a+b relative humidity +c age +d weight (p0.001).We have developed new mathematical equations for calculating the optimal temperature for the incubator air as a function of the latter's relative humidity. The software constitutes a decision support tool for improving patient care in routine clinical practice.

Mathematical models of body heat exchanges can be used to define the thermal limits needed to protect premature neonates nursed in incubators against thermal stress–stress that can have potentially devastating impairments on neurological development and body growth. Predictive models can help caregivers to keep a neonate’s body temperature within the normal range and to solve problems that arise during intensive care, such as the risk of hyperthermia during phototherapy, the risk of hypothermia during transport from one clinical centre to another, and the use of a plastic bag to reduce skin water loss and body dehydration. Here, we review the strengths and limitations of models used to predict the risk of thermal stress, with a focus on uncertainties in the algorithms governing heat transfers between the neonate’s skin and the complicated thermal environment encountered in incubators. We describe attempts to reduce the large number of empirical assumptions and uncertainties in this field, and suggest ways of more accurately modelling optimal thermal conditions for neonates nursed in closed incubators.

The efficacy and safety of three polyethylene bags commonly used to prevent hypothermia in premature infants was assessed.To simulate transfer from the delivery room to a secondary care unit, a thermally stable, bonneted mannequin (skin temperature: 34.4 °C) was placed in a climate chamber under different conditions: with a radiant warmer, with various polyethylene bags (open on one side, closed by a draw-string at the neck, or a "life support pouch" with several access points) or without a bag.With the radiant warmer turned on, the mean reduction in heat loss from the nude mannequin was 50.8 ± 1.7% (p 0.0001, vs. warmer off). The mean reduction in heat loss (vs. no bag) was 55.0 ± 0.9% for the drawstring bag, 49.0 ± 2.2% for the standard bag (p = 0.0001), and 48.1 ± 0.7% for the life support pouch (p = 0.006). When a radiant warmer + polyethylene bag were used, heat stress (body temperature: 38 °C) and severe hyperthermia (40 °C) occurred after 11 and 34 min, respectively.Caution must be taken when using a radiant warmer and polyethylene bag with a premature infant. Heat stress can occur in only 11 min. Continuous body temperature monitoring is therefore required.

In the delivery room, wrapping a low-birth-weight neonate (defined as ≤2.499 g) in a polyethylene bag reduces the risk of hypothermia. However, extended use of the bag (e.g., during neonatal surgery) might conceivably increase the risk of thermal stress and thus body overheating. Here, we assessed the efficacy of a polyethylene bag in infants assigned to wrap (W) or nonwrap (NW, control) groups during placement of a percutaneous vena cava catheter by applying a new mathematical model that calculates heat exchanges for covered and uncovered body segments. At the end of the placement procedure, the W and NW groups did not differ significantly in terms of whole-body heat loss (15.80 versus 14.97 kJ·h−1·kg−1, resp.), whereas the abdominal skin temperature was slightly but significantly higher (by 0.32°C) in the W group. Greater evaporation in the W group (2.49 kJ·h−1·kg−1) was primarily balanced by greater whole-body radiant heat loss (3.44 kJ·h−1·kg−1). Wrapping the neonate in a polyethylene bag provides a small thermal benefit when catheter placement takes a long time. Given that polyethylene is transparent to radiant energy, it might be of value to incorporate polymers that are less transparent at infrared wavelengths.

NDR : Ce dossier donne a entendre plusieurs voix, celle de l’auteur de la piece (R. Sued), celles de ses personnages (Eugenie, Maria et les autres), celle d’une spectatrice (A. Garcia Castro), celle d’un comedien et metteur en scene (G. Reyna). Un mot semble necessaire sur les conditions de travail car celles-ci renvoient, en partie, a la piece elle-meme et a sa specificite la plus evidente (elle se deroule dans l’obscurite et, selon le mot d’Estelle Durand, traite « de la force de la reminis...

Previous studies suggested that defective arousal might be a major mechanism in sleep-disordered breathing such as sudden infant death syndrome and obstructive sleep apnea. In this study, we examined the effects of intermittent hypoxia (IH) on the arousal response to hypoxia in 4-day-old mice. We hypothesized that IH would increase arousal latency, as previously reported in other species, and we measured the concomitant changes in ventilation to shed light on the relationship between breathing and arousal. Arousal was scored according to behavioral criteria. Breathing variables were measured noninvasively by use of whole-body flow plethysmography. In the hypoxic group ( n = 14), the pups were exposed to 5% O2 in N2 for 3 min and returned to air for 6 min. This test was repeated eight times. The normoxic mice ( n = 14) were constantly exposed to normoxia. The hypoxic mice showed a 60% increase in arousal latency ( P < 0.0001). Normoxic controls showed virtually no arousals. IH depressed normoxic ventilation below baseline prehypoxic levels, while preserving the ventilatory response to hypoxia. The breathing pattern and arousal responses recovered fully after 2 h of normoxia. We conclude that IH rapidly and reversibly depressed breathing and delayed arousal in newborn mice. Both effects may be due to hypoxia-induced release of inhibitory neurotransmitters acting concomitantly on both functions.

The aim of the present study was to test whether breathing pattern conditioning may occur just after birth. We hypothesized that sensory stimuli signaling the resumption of maternal care after separation may trigger an arousal and/or orienting response accompanied with concomitant respiratory changes. We performed a conditioning experiment in 2-day-old mice by using an odor (lemon) as the conditioned stimulus (CS) and maternal care after 1 h without the mother as the unconditioned stimulus (US). Each pup underwent two acquisition trials, in which the CS was presented immediately before (experimental paired group, n = 30) or 30 min before (control unpaired group, n = 30) contact with the mother. Conditioning was tested by using noninvasive whole body plethysmography to measure the respiratory response to the CS for 1 min. We found significantly stronger respiratory responses to the CS in the experimental group than in the control group. In contrast, somatomotor activity did not differ significantly between groups. Our results confirm the sensitivity of breathing to conditioning and indirectly support the hypothesis that learned feedforward processes may complement feedback pathways during postnatal maturation of respiratory control.

The c-ret proto-oncogene encodes a tyrosine-kinase receptor involved in survival and differentiation of neural crest cell lineages. Previous studies have shown that homozygous c-ret-/- mice die soon after birth and have impaired ventilatory responses to hypercapnia. Heterozygous c-ret +/- mice develop normally, but their respiratory phenotype has not been described in detail. We used whole-body flow plethysmography to compare baseline breathing and ventilatory and arousal responses to chemical stimuli in unrestrained heterozygous c-ret +/- newborn mice and their wild-type c-ret +/+ littermates at 10-12 h of postnatal age. The hyperpnoeic and arousal responses to hypoxia and hypercapnia were not significantly different in these two groups. However, the number and total duration of apnoeas and periodic breathing episodes were significantly higher in c-ret +/- than in c-ret +/+ pups during hypoxia and post-hypoxic normoxia. These results are further evidence that respiratory control at birth is heavily dependent on genes involved in the neural determination of neural crest cells.

La recherche « Conditions d'acceptation d'un scenario Vivre Post Carbone » interroge, sous l'angle sociologique, la reception, par les habitants des territoires concernes, du scenario « Vivre Post Carbone 2030 »pour le perimetre du SCoT (Schema de Coherence territoriale) de l'agglomeration tourangelle (37). Une trentaine d'entretiens qualitatifs ont ete realises aupres de menages tourangeaux d'âges, de niveaux de revenus et de lieux de residence differents. La question des impacts et des couts sociaux du scenario, plus globalement de son acceptabilite par les habitants, constitue la trame des resultats. Le scenario est, en effet, diversement recu par les interviewes en fonction de leurs contraintes objectives et de la perception de leurs propres marges de manœuvre. Dans tous les cas, les elements du scenario apparaissent comme d'autant plus credibles, acceptables et « desirables »qu'ils convoquent des echelles de temps et d'espace appropriables par les individus. Loin d'adopter une position d'objection ou d'hostilite de principe a tout changement, les menages rappellent que l'enjeu principal pour eux reste le maintien et/ou l'amelioration de leurs cadres et modes de vie.

// Lucille Lopez-Delisle 1,2 , Cecile Pierre-Eugene 1,2 , Evelyne Bloch-Gallego 3,4 , Marie-Christine Birling 5 , Jean-Loup Duband 6,7 , Estelle Durand 8 , Thomas Bourgeois 8 , Boris Matrot 8,9 , Tania Sorg 5 , Michel Huerre 10 , Hamid Meziane 5 , Michel J. Roux 5 , Marie-France Champy 5 , Jorge Gallego 9 , Olivier Delattre 1,2 , Isabelle Janoueix-Lerosey 1,2 1 Inserm U830, Paris, France; 2 Institut Curie, Centre de Recherche, Paris, France; 3 Institut Cochin, Universite Paris Descartes, CNRS (UMR 8104), Paris, France; 4 Inserm, U1016, Paris, France; 5 Institut Clinique de la Souris, Illkirch-Graffenstaden, France; 6 Sorbonne Universites, Universite Pierre et Marie Curie-Paris 6, Paris, France; 7 CNRS, Laboratoire de Biologie du Developpement, Paris, France; 8 PhenoPups SAS, Evry, France; 9 Inserm U1141, Hopital Robert Debre, Paris, France; 10 Institut Curie, Departement de Pathologie, Paris, France. Correspondence: Isabelle Janoueix-Lerosey, email: // Keywords : ALK, brainstem, neonatal lethality, plethysmography, feeding difficulties Received : March 24, 2014 Accepted : April 01, 2014 Published : April 02, 2014 Abstract The ALK (Anaplastic Lymphoma Kinase) gene encodes a tyrosine kinase receptor preferentially expressed in the central and peripheral nervous systems. A syndromic presentation associating congenital neuroblastoma with severe encephalopathy and an abnormal shape of the brainstem has been described in patients harbouring de novo germline F1174V and F1245V ALK mutations. Here, we investigated the phenotype of knock-in (KI) mice bearing the Alk F1178L mutation (F1174L in human). Although heterozygous KI mice did not reproduce the severe breathing and feeding difficulties observed in human patients, behavioral tests documented a reduced activity during dark phases and an increased anxiety of mutated mice. Matings of heterozygotes yielded the expected proportions of wild-type, heterozygotes and homozygotes at birth but a high neonatal lethality was noticed for homozygotes. We documented Alk expression in several motor nuclei of the brainstem involved in the control of sucking and swallowing. Evaluation of basic physiological functions 12 hours after birth revealed slightly more apneas but a dramatic reduced milk intake for homozygotes compared to control littermates. Overall, our data demonstrate that Alk activation above a critical threshold is not compatible with survival in mice, in agreement with the extremely severe phenotype of patients carrying aggressive de novo ALK germline mutations.

Spinal muscular atrophy (SMA) is caused by insufficient levels of the survival motor neuron (SMN) protein leading to muscle paralysis and respiratory failure. In mouse, introducing the human SMN2 gene partially rescues Smn(-)(/)(-) embryonic lethality. However current models were either too severe or nearly unaffected precluding convenient drug testing for SMA. We report here new SMN2;Smn(-/-) lines carrying one to four copies of the human SMN2 gene. Mice carrying three SMN2 copies exhibited an intermediate phenotype with delayed appearance of motor defects and developmental breathing disorders reminiscent of those found in severe SMA patients. Although normal at birth, at 7 days of age respiratory rate was decreased and apnea frequency was increased in SMA mice in parallel with the appearance of neuromuscular junction defects in the diaphragm. With median survival of 15 days and postnatal onset of neurodegeneration, these mice could be an important tool for evaluating new therapeutics.

Introduction Les lignees de souris genetiquement modifiees presentent souvent une mortalite neonatale attribuee a une atteinte respiratoire, qui exclut toute analyse in vivo. La realisation d’une ventilation mecanique neonatale, inexistante a ce jour, doit permettre de surmonter cette difficulte. Nous presentons ici un dispositif original de ventilation non invasive par pression negative couple a un dispositif optique permettant une ventilation controlee ou assistee chez le souriceau nouveau-ne. Methodes Le souriceau est place dans un caisson hermetique (de type « poumon d’acier »), la tete a l’exterieur. Une enceinte peut etre disposee autour de la tete pour creer une pression expiratoire positive (PEP), et/ou administrer des aerosols. Une pression negative intermittente est appliquee autour du thorax et provoque une ventilation mecanique. En mode assiste, des cycles de ventilation sont declenches par un trigger qui detecte toute deformation thoraco-abdominale inspiratoire grâce a un dispositif optique. Pour tester le ventilateur, des souriceaux ont ete exposes a l’inhalation forcee de 10 % d’isoflurane pendant 3 minutes le jour de la naissance (P0) ou a P1. Apres une minute d’arret cardiorespiratoire, les souriceaux ont ete repartis en deux groupes : ventiles (en mode controle, n = 50) et non-ventiles (n = 48), et nous avons compare les taux de survie dans chaque groupe. Le ventilateur a aussi ete teste en mode assiste a P0 et P7 sur un autre groupe de souris exposes ou non a l’isoflurane. Resultats Les taux de survie dans le groupe reanime par ventilation controlee et le groupe non-reanime sont respectivement de 90 % et 25 %. Les souriceaux reanimes ont montre un developpement physiologique normal a P2 et P7, ce qui suggere l’absence de sequelles pulmonaires graves. En ventilation assistee, le temps de reponse du ventilateur est inferieur a 20 % de la duree d’inspiration. Le volume courant des cycles assistes est augmente significativement, indiquant la possibilite d’une ventilation assistee non invasive, et la mise en œuvre de protocoles de sevrage. Conclusion Ce ventilateur doit permettre de diminuer la mortalite neonatale de certaines lignes de souris genetiquement modifiee, permettre leur analyse in vivo et tester des traitements sous forme d’aerosols.

Central congenital hypoventilation syndrome (CCHS) is a rare autosomal dominant syndrome present from birth, and characterized by depressed ventilation during sleep. Heterozygous mutations of the homeobox gene Phox2b were recently found in a very high proportion of patients.To determine whether newborn mice with heterozygous targeted deletion of the transcription factor Phox2b would display sleep-disordered breathing.We measured breathing pattern using whole-body plethysmography in wild-type and mutant 5-day-old mice, and we classified sleep-wake states using nuchal EMG and behavioral scores.We found that sleep apnea total time was approximately six times longer (8.9 +/- 12 vs. 1.5 +/- 2.2 seconds, p0.0015), and ventilation during active sleep was 21% lower (18.4 +/- 5.1 vs. 23.3 +/- 5.5 ml/g/second, p0.006) in mutant than in wild-type pups. During wakefulness, apnea time and ventilation were not significantly different between mutant and wild-type pups. Mutant and wild-type pups showed highly similar sleep-wake states.Although their respiratory phenotype was much less severe than CCHS, the Phox2b(+/-) mutant mice showed sleep-disordered breathing, which partially modeled the key feature of CCHS.

An increasing number of studies in newborn mice are being performed to determine the mechanisms of sleep apnea, which is the hallmark of early breathing disorders. Whole body plethysmography is the method of choice, as it does not require immobilization, which affects behavioral states and breathing. However, activity inside the plethysmograph may disturb the respiratory signal. Visual classification of the respiratory signal into ventilatory activity, activity-related disturbances, or apneas is so time-consuming as to considerably hamper the phenotyping of large pup samples. We propose an automatic classification of activity based on respiratory disturbances and of apneas based on spectral analysis. This method was validated in newborn mice on the day of birth and on postnatal days 2, 5, and 10, under normoxic and hypoxic (5% O2) conditions. For both activity and apneas, visual and automatic scores showed high Pearson's correlation coefficients (0.92 and 0.98, respectively) and high intraclass correlation coefficients (0.96–0.99), supporting strong agreement between the two methods. The present results suggest that breathing disturbances may provide a valid indirect index of activity in freely moving newborn mice and that automatic apnea classification based on spectral analysis may be efficient in terms of precision and of time saved.

Determining the behavioural phenotype of genetically altered mice is a valuable approach for elucidating the function of genes and their role in cognitive disorders. Methods for phenotyping newborn mice are scarce and generally confined to sensorimotor reflexes. Here, we describe a simple method for assessing associative abilities in newborn mice. We used a two-odour-choice classical conditioning paradigm in mice from the day of birth (post-natal age 0, P0) to P6. Acquisition required 20 trials: 10 trials during which the pups were placed over the conditioned stimulus (CS+) odour (lemon or peppermint) for 30s and simultaneously stroked gently with a paintbrush and 10 trials during which the pups were placed over the other odour (CS-) for 30s, without stroking. Then, the pups were subjected to five odour-preference trials to test for conditioning. This sequence of five trials was repeated after 5 and 24h to assess retention of the conditioned odour preference. During the immediate post-acquisition sequence, the pups spent significantly more time over the CS+ than over the CS- (p

International audience; AIM: To study the ventilatory and arousal/defence responses to hypoxia in newborn mutant mice lacking the beta2 subunit of the nicotinic acetylcholine receptors. METHODS: Breathing variables were measured non-invasively in mutant (n = 31) and wild-type age-matched mice (n = 57) at 2 and 8 days of age using flow barometric whole-body plethysmography. The arousal/defence response to hypoxia was determined using behavioural criteria. RESULTS: On day 2, mutant pups had significantly greater baseline ventilation (16%) than wild-type pups (P < 0.02). Mutant pups had a decreased hypoxic ventilatory declines. Arousal latency was significantly shorter in mutant than in wild-type pups (133 +/- 40 vs. 146 +/- 20 s, respectively, P < 0.026). However, the duration of movement elicited by hypoxia was shorter in mutant than in wild-type pups (14.7 +/- 5.9 vs. 23.0 +/- 10.7 s, respectively, P < 0.0005). Most differences disappeared on P8, suggesting a high degree of functional plasticity. CONCLUSION: The blunted hypoxic ventilatory decline and the shorter arousal latency on day 2 suggested that disruption of the beta2 nicotinic acetylcholine receptors impaired inhibitory processes affecting both the ventilatory and the arousal response to hypoxia during postnatal development.

In this study, we describe a simple and inexpensive method for inducing short-term anesthesia and rapid recovery in newborn mice. Litters of Swiss mice pups were randomly allocated to testing on postnatal days 2, 5, and 8. Anesthesia was induced by placing the pup in a syringe and adding a volume of isoflurane-saturated gas that produced an estimated level of 32% isoflurane. Exposure to isoflurane lasted 30 s. All the pups survived the anesthesia. At all study ages, this method abolished the nociceptive response to tail clamp without inducing mortality, thus showing effective anesthesia. Recovery from anesthesia was assessed immediately after isoflurane exposure, based on two nonnoxious behavioral tests: the defensive response to a drop of water (10 tests, 1 min apart) and 10 min later the righting reflex, i.e., the time to recovery of the prone position (five tests, 10 min apart). The water drop test scores increased during the recovery phase toward the control values in all age groups. Treatment and time had no significant effect on righting reflex scores. The initial volume in the syringe, the volume of added isoflurane-saturated gas, and the duration of exposure may be adjusted according to postnatal age and specific strains or species (e.g., rats). This method is well suited to behavioral or physiological phenotype studies in developing mice, in which noxious procedures must precede functional testing, making rapid recovery from anesthesia a key requirement.

We examined the arousal response to 5% O 2 in newborn mice at several ages before and after peripheral chemoreceptor resetting, namely, at 3, 12, and 48 h ( n =22 in each group). Breathing was measured by whole-body flow barometric plethysmography. Sleep and arousal were determined behaviourally. We found that: (1) the arousal response was present in all age groups; (2) the arousal response occurred during the hypoxic ventilatory decline in all age groups, showing that mechanoreceptor input was not sufficient to trigger arousal; and (3) arousal latency was shorter after than before chemoreceptor resetting, suggesting a contribution of chemoreceptors to arousal. We conclude that arousal may contribute to the hypoxic ventilatory response in the early postnatal period in mice and that it should be taken into consideration in studies of ventilatory control maturation in newborns.

In this article, it is argued that learning participates to fulfill the metabolic requirements by adapting respiratory control to changing internal and external states. Recent classical conditioning experiments in newborn mice or adult rats showthe close link between conditioned respiratory and arousal responses. The conditioned fear model may be a suitable and largely unexplored model of emotionally induced hyperventilation. The parabrachial nucleus and periacqueducal grey may play a pivotal role in the ventilatory component of conditioned fear. The sensitivity of breathing to conditioning in newborn and adult animals suggests that learning processes may shape breathing pattern throughout life.

Le bénévolat doit aujourd’hui être considéré comme un temps social particulier, entre le temps libéré du travail (temps libre) et le temps de loisirs. L’article rappelle les étapes de la conquête du temps libre et la place tenue progressivement par les loisirs. Dans ce contexte, le temps de bénévolat occupe une position spécifique, dont la particularité provient principalement de sa constitution socio-historique, puisque le bénévolat se situe entre l’action individuelle et l’action collective, entre l’activité pour soi et l’activité tournée vers autrui. L’altruisme se substitue à la charité dans une nouvelle forme de don. L’auteur montre que le bénévolat s’inscrit dans un type de don et un type de solidarité qui lui sont propres : le don bénévole., Volunteering should today be considered as a specific social time between the time that is freed from work (free time) and the time spent on leisure activities. The article retraces the stages of the development of free time and the growth of leisure. Within this context, the time spent volunteering occupies a particular position. Its specificity mainly derives from its socio-historical construction as volunteering lies between individual action and collective action or between activity for oneself and activity directed towards others. Altruism has replaced charity in a new form of giving. The author shows that volunteering has its own type of giving and solidarity that could be called the “volunteering gift.”