Plamen Bokov

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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(More)
BACKGROUND AND OBJECTIVE Changes in specific airway resistance (ΔsRaw) after bronchodilation, as measured by plethysmography and FEV(1) , are frequently considered to be interchangeable indices of airway obstruction. However, the baseline relationship between these two indices is weak, and the value of ΔsRaw that best predicts FEV(1) reversibility in(More)
BACKGROUND Gas 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 PATIENTS Forced expiratory flows (FEV(1),(More)
Computational hemodynamic models of the cardiovascular system are often limited to finite segments of the system and therefore need well-controlled inlet and outlet boundary conditions. Classical boundary conditions are measured total pressure or flow rate imposed at the inlet and impedances of RLR, RLC, or LR filters at the outlet. We present a new(More)
BACKGROUND While lung hyperinflation is frequent in asthma, measurement of lung volumes is not recommended in current guidelines. The aim of this descriptive functional study was to assess whether systematic measurement of volumes by plethysmography may detect isolated hyperinflation with normal expiratory flows. METHODS AND PATIENTS One hundred sixty(More)
The asymmetry of the bronchial tree has been reported on numerous occasions, and bronchi in the lung bifurcate most of the time into a major and a minor daughter. Asymmetry is most probably bound to play a role on the hydrodynamic resistance and volume occupation of the bronchial tree. Thus, in this work, we search for an optimal asymmetric airway tree(More)
BACKGROUND The earliest changes associated with airflow obstruction in asthmatic children are a proportionally greater reduction in FEF(50%) than in FEV(1) using spirometry, and an increase in specific airway resistance (sRaw) using body plethysmography. Consequently, we hypothesized that sRaw could be better linked to FEF(50%) than to FEV(1). The first aim(More)
BACKGROUND The aims of the study were: (1) to compare numerical parameters of specific airway resistance (total, sRaw(tot), effective, sRaw(eff) and at 0.5 L · s(-1), sRaw(0.5)) and indices obtained from the forced oscillation technique (FOT: resistance extrapolated at 0 Hz [Rrs(0 Hz)], mean resistance [Rrs(mean)], and resistance/frequency slope(More)
PURPOSE Early artery wall-thickening detected by ultrasound-assessed increased carotid intima-media thickness (IMT) may reflect atherosclerosis or represent an adaptive response to keep homeostasis tensile stress that is related inversely to wall thickness by Laplace's equation. We attempted to discriminate between both mechanisms by correcting IMT for its(More)
BACKGROUND Specific airway resistance (sRaw) is virtually independent of lung growth, height, and gender, thus facilitating longitudinal follow-up. OBJECTIVE To assess whether a specific phenotype of asthmatic children with a decline in lung function can be evidenced using sRaw. METHODS The authors hypothesized that sequential sRaw measurements over a(More)