Protective effects of intermittent hypoxia on brain and memory in a mouse model of apnea of prematurity

International audienceApnea of prematurity (AOP) is considered a risk factor for neurodevelopmental disorders in children based on epidemiological studies. This idea is supported by studies in newborn rodents in which exposure to intermittent hypoxia (IH) as a model of AOP significantly impairs development. However, the severe IH used in these studies may not fully reflect the broad spectrum of AOP severity. Considering that hypoxia appears neuroprotective under various conditions, we hypothesized that moderate IH would protect the neonatal mouse brain against behavioral stressors and brain damage. On P6, each pup in each litter was randomly assigned to one of three groups: a group exposed to IH while separated from the mother (IH group), a control group exposed to normoxia while separated from the mother (AIR group), and a group of untreated unmanipulated pups left continuously with their mother until weaning (UNT group). Exposure to moderate IH (8% O2) consisted of 20 hypoxic events/hour, 6 h per day from postnatal day 6 (P6) to P10. The stress generated by maternal separation in newborn rodents is known to impair brain development, and we expected this effect to be smaller in the IH group compared to the AIR group. In a separate experiment, we combined maternal separation with excitotoxic brain lesions mimicking those seen in preterm infants. We analyzed memory, angiogenesis, neurogenesis and brain lesion size. In non-lesioned mice, IH stimulated hippocampal angiogenesis and neurogenesis and improved short-term memory indices. In brain-lesioned mice, IH decreased lesion size and prevented memory impairments. Contrary to common perception, IH mimicking moderate apnea may offer neuroprotection, at least in part, against brain lesions and cognitive dysfunctions related to prematurity. AOP may therefore have beneficial effects in some preterm infants. These results support the need for stratification based on AOP severity in clinical trials of treatments for AOP, to determine whether in patients with moderate AOP, these treatments are beneficial or deleterious

Hyperactivation of Alk induces neonatal lethality in knock-in AlkF1178L mice

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 AlkF1178L 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

Rapport V. c-6. L’hydraulique dans les tracteurs agricoles

In addition to the usual brake and assisted-steering applications, hydraulics are also widely used for farm tractor implement attachment and control systems, affording closer control over the work done whilst increasing tractive effort. Improvements to these systems have led to greater accuracy and sensitivity under working conditions and for different implements used. Hydrostatic transmissions are also arousing considerable interest as they have certain features that are very suitable for farm tractor applications.En dehors des applications classiques à la commande des freins et à l’assistance de la direction, l’hydraulique est très largement utilisée sur les tracteurs agricoles dans les systèmes d’attelage des outils pour opérer le relevage et surtout le contrôle du travail tout en augmentant la capacité de traction du tracteur. L’évolution de ces systèmes a conduit à des perfectionnements permettant d’obtenir précision et sensibilité dans les différentes conditions de travail et pour les divers genres d’instruments. Par ailleurs, les transmissions hydrostatiques dont certaines caractéristiques conviennent bien aux tracteurs suscitent un grand intérêt.Matrot L. Rapport V. c-6. L’hydraulique dans les tracteurs agricoles. In: Le rôle de la mécanique des fluides dans les progrès récents des techniques. 1967

CETIOM Stratégie plein champ : Oléopro 2002

Pour la filière oléoprotéagineuse française, Oléopro 2002 aura été l’événement médiatique marquant de l’année 2002, le « premier salon au champ des oléoprotéagineux ». Il s’est déroulé les 12 et 13 juin 2002 près de Bourges et a réuni 18 000 visiteurs venus de toute la France, principalement des producteurs. À l’échelle de la filière oléoprotéagineuse, c’est un succès puisque 90% des visiteurs indiquent que la visite a répondu à leur attente, et que 98% des exposants se disent satisfaits des contacts réalisés. Le concept qui a conduit à ce succès est apparemment simple : présenter sur 40 hectares et 4 000 m2 de tentes toutes les offres de progrès susceptibles d’intéresser les producteurs d’oléagineux et de protéagineux, de façon démonstrative et conviviale, le tout au grand air. Offres techniques d’une part, à travers 4 ha de micro-parcelles de démonstration mises en place par le Cetiom et l’UNIP 2-ITCF 3. Offres technico-commerciales d’autre part avec la présence de 56 sociétés exposantes, représentant aussi bien l’amont que l’aval de la production, ainsi que les organisations professionnelles du secteur

Contribution à l'étude des salmonelles en élevage porcin

LYON1-BU Santé (693882101) / SudocSudocFranceF

Arousal response to hypoxia in newborns: Insights from animal models

International audienc

CETIOM Stratégie plein champ : Oléopro 2002

Pour la filière oléoprotéagineuse française, Oléopro 2002 aura été l’événement médiatique marquant de l’année 2002, le « premier salon au champ des oléoprotéagineux ». Il s’est déroulé les 12 et 13 juin 2002 près de Bourges et a réuni 18 000 visiteurs venus de toute la France, principalement des producteurs. À l’échelle de la filière oléoprotéagineuse, c’est un succès puisque 90% des visiteurs indiquent que la visite a répondu à leur attente, et que 98% des exposants se disent satisfaits des contacts réalisés. Le concept qui a conduit à ce succès est apparemment simple : présenter sur 40 hectares et 4 000 m2 de tentes toutes les offres de progrès susceptibles d’intéresser les producteurs d’oléagineux et de protéagineux, de façon démonstrative et conviviale, le tout au grand air. Offres techniques d’une part, à travers 4 ha de micro-parcelles de démonstration mises en place par le Cetiom et l’UNIP 2-ITCF 3. Offres technico-commerciales d’autre part avec la présence de 56 sociétés exposantes, représentant aussi bien l’amont que l’aval de la production, ainsi que les organisations professionnelles du secteur

Transgenic Models to Study Disorders of Respiratory Control in Newborn Mice

International audienc

Comparison of methods of chemical loop gain measurement during tidal ventilation in awake healthy subjects

International audienceThe loop gain (LG) is defined as the ratio of a ventilatory response over the perturbation in ventilation, and it is used to analyze ventilatory control stability. The LG can be derived from minute ventilation (VE), end-tidal PCO2 (PETCO2) and PETO2 values. Several methods of LG assessment have been developed, which have never been compared. We evaluated the computability, the short term repeatability and the agreement of six published (or slightly modified) models for LG determination. These models included three unconstrained autoregressive models: univariate (VE), bivariate (VE, PETCO2) and trivariate (VE, PETCO2 and PETO2) and three analytical transfer function constrained models based on VE, VE and CO2-sensitivity, and VE, central and peripheral CO2-sensitivities, respectively. The models were tested using tidal breathing data in 37 awake healthy subjects (median age, 35 years, 23 women). Modelling failed in 11, 0, and 0 subjects for the three unconstrained models respectively, and 4, 1, and 9 subjects for the three constrained models, respectively. Bland and Altman analyses of the LG values in the medium frequencies range of two separate recordings demonstrated good repeatability for four models, excluding univariate and trivariate unconstrained models. The four repeatable models gave LG values that were in agreement (medium frequencies LG, median 0.100 to 0.210), although the constrained model based on VE systematically overestimated LG values. The variances explained by these models were around 20%. In conclusion, model-based analyses of tidal breathing were performed using different approaches that give comparable results of chemical LG and explained variance