Developmental Patterning by Mechanical Signals in Arabidopsis

A central question in developmental biology is whether and how mechanical forces serve as cues for cellular behavior and thereby regulate morphogenesis. We found that morphogenesis at the Arabidopsis shoot apex depends on the microtubule cytoskeleton, which in turn is regulated by mechanical stress. A combination of experiments and modeling shows that a feedback loop encompassing tissue morphology, stress patterns, and microtubule-mediated cellular properties is sufficient to account for the coordinated patterns of microtubule arrays observed in epidermal cells, as well as for patterns of apical morphogenesis

Relationships between Specific Airway Resistance and Forced Expiratory Flows in Asthmatic Children

. The first aim was to assess the relationships between forced expiratory flows and sRaw in a large group of asthmatic children in a transversal study. We then performed a longitudinal study in order to determine whether sRaw of preschool children could predict subsequent impairment of forced expiratory flows at school age.Pulmonary function tests (sRaw and forced expiratory flows) of 2193 asthmatic children were selected for a transversal analysis, while 365 children were retrospectively selected for longitudinal assessment from preschool to school age. (% predicted) (−0.09, 95% CI, −0.20 to 0). and could be used in preschool children to predict subsequent mild airflow limitation

Description expérimentale et numérique de l'interaction entre un stent biodégradable et la paroi artérielle

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

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

Boundary conditions in arterial flows and evaluation of reflection indices

International audienc

Gas trapping is associated with severe exacerbation in asthmatic children

SummaryBackgroundGas trapping suggesting small airway disease is observed in adult asthmatic suffering from severe asthma. The aim of the study was to assess whether gas trapping could be evidenced in asthmatic children with/without severe exacerbation and with/without symptoms during the past three months.Methods and patientsForced expiratory flows (FEV1, FVC, MEF25–75%, MEF50%), plethysmographic lung volumes (TLC, FRC, RV) before and after bronchodilation (BD) were recorded in asthmatic children with documented airflow reversibility. Three groups were defined according to the presence during the last three months of 1) severe exacerbation (oral steroid: 3 consecutive days) 2) asthma symptoms without severe exacerbation and 3) without any symptom (GINA guidelines).Results180 children (median 11.3 years, range 6.3–17.6, 57 girls) were included, 24 (13%) had at least one severe exacerbation, 58 (33%) had respiratory symptoms without severe exacerbation and 98 (54%) had no symptom during the past 3 months. Forced expiratory flows did not significantly differ in these three groups, while RV/TLC was significantly higher in the first group before and even after bronchodilation: before BD, 0.27 ± 0.07, 0.24 ± 0.05 and 0.23 ± 0.05, respectively (p = 0.016) and after BD, 0.25 ± 0.07, 0.21 ± 0.05, 0.21 ± 0.05, respectively (p = 0.003).ConclusionIn asthmatic children, gas trapping is associated with occurrence of a severe exacerbation during the last three months, suggesting a small airway disease that is not evidenced by forced expiratory flows