Slower Is Higher: Threshold Modulation of Cortical Activity in Voluntary Control of Breathing Initiation

Speech or programmed sentences must often be interrupted in order to listen to and interact with interlocutors. Among many processes that produce such complex acts, the brain must precisely adjust breathing to produce adequate phonation. The mechanism of these adjustments is multifactorial and still poorly understood. In order to selectively examine the adjustment in breath control, we recorded respiratory-related premotor cortical potentials from the scalp of human subjects while they performed a single breathing initiation or inhibition task. We found that voluntary breathing is initiated if, and only if, the cortical premotor potential activity reaches a threshold activation level. The stochastic variability in the threshold correlates to the distribution of initiation times of breathing. The data also fitted a computerized interactive race model. Modeling results confirm that this model is also as effective in respiratory modality, as it has been found to be for eye and hand movements. No modifications were required to account for respiratory cycle inhibition processes. In this overly simplified task, we showed a link between voluntary initiation and control of breathing and activity in a fronto-median region of the cerebral cortex. These results shed light on some of the physiological constraints involved in the complex mechanisms of respiration, phonation, and language

Self-Assembling Bisbenzimidazole Derivatives: A Pioneering Approach to Bacterial Flocculation

peer reviewe

Exploring the antibacterial potential of bisbenzimidazole compounds with remarkable physico-chemical and biological properties

peer reviewe

Detection of the Enzymatic Cleavage of DNA through Supramolecular Chiral Induction to a Cationic Polythiophene

International audienc

Rhinitis in subjects with work-exacerbated asthma.

OBJECTIVES: This study aimed at characterizing the nature, severity, and timing of nasal and ocular symptoms in subjects with work-exacerbated asthma (WEA). METHODS: Among the 363 subjects referred to a tertiary-care hospital for the investigation of work-related asthma symptoms, 105 subjects who demonstrated non-specific bronchial hyperresponsiveness to histamine, but a negative response to a specific inhalation challenge with the suspected occupational agent(s) were considered as having WEA. Their characteristics were compared with those of 172 subjects with occupational asthma (OA), ascertained by a positive response to a specific inhalation challenge. RESULTS: A high proportion of subjects with WEA (83%) and OA (90%) reported at least one nasal symptom at work. Sneezing/itching and rhinorrhea were more frequent in subjects with OA (78% and 70%, respectively) than in those with WEA (61%, p = 0.004 and 57%, p = 0.038, respectively), while post-nasal discharge was more common in WEA (30%) than in OA (18%, p = 0.019). Nasal symptoms were less severe in WEA (median [25th-75th percentiles] global severity score: 4 [2-6]) as compared to OA (5 [4-7], p < 0.001). Nasal symptoms preceded less frequently those of asthma in subjects with WEA (17%) than in subjects with OA (43%, p = 0.001). CONCLUSIONS: Nasal symptoms are highly prevalent in subjects with WEA, although their clinical pattern differs from that found in OA. Further investigations of the health and socio-economic impacts of upper airways symptoms in WEA are required to improve the understanding and management of this common condition

Investigation of Occupational Asthma Sputum Cell Counts or Exhaled Nitric Oxide?

Background: The measure of sputum eosinophil counts is a useful tool in the investigation of occupational asthma (OA), but processing sputum is time consuming. Measuring the fractional concentration of exhaled nitric oxide (FENO) may be an alternative in clinical practice. The aim of this study was to assess the respective changes of sputum eosinophil counts and FENO following exposure to occupational agents in the routine practice of two tertiary centers in North America and Europe. Methods: Workers undergoing specific inhalation challenges (SICs) for possible OA in tertiary clinics in both Canada and Belgium were enrolled. Sputum cell counts and FENO were collected at the end of the control day and at 7 and 24 h after exposure to the offending agent. Results: Forty-one subjects had a negative SIC; 26 subjects had OA proven by a positive SIC. In subjects with positive SIC, there was a significant increase in sputum eosinophils at 7 h (9.0 [9.9]%) and 24 h (11.9 [14.9]%) after exposure compared with the baseline (2.8 [4.2]%), whereas there was a significant increase in FENO only, 24 h after exposure (26.0 [30.5] ppb) compared with the baseline (16.6 [18.5] ppb). A 2.2% change in sputum eosinophil counts achieved a much higher sensitivity and positive predictive value than a 10-ppb change in FENO with similar specificity and negative predictive value for predicting a 20% decrease in FEV1 during SICs. Conclusions: Sputum eosinophil counts constitute a more reliable tool than FENO to discriminate positive and negative SICs. CHEST 2010; 137(3):617-62

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in nasal lavage after an inhalation challenge with flour.

This study showed that after an inhalation challenge with an occupational allergen, the nasal mucosa displayed an imbalance in favor of TIMPs enzymes activity as compared to MMPs enzymes activity, represented in an increase in nasal levels of TIMP-2 during the course of the early reaction following the allergen challenge

Matrix Metalloproteinase-9 Increases in the Sputum from Allergic Occupational Asthma Patients after Specific Inhalation Challenge.

Background: Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) play a role in the pathogenesis of asthma. MMP-9 increases in the sputum of asthmatic patients after bronchial challenge with common allergens. We sought to assess whether a high-molecular-weight occupational allergen was able to induce changes in MMP-9 as well as in other MMPs and TIMPs in subjects with occupational asthma. Methods: Ten patients underwent specific inhalation challenge (SIC) on 2 consecutive days. We monitored changes in lung function by measuring FEV(1) for 7 h. Induced sputum test was performed at 6 h after sham and flour challenge. The total and differential cell counts were analyzed. Levels of MMPs (specifically MMP-2, MMP-7, MMP-9 and MMP-13) were measured using Fluorokine® MultiAnalyte Profiling kits and a Luminex® Bioanalyzer, while levels of TIMP-1 and TIMP-2 were measured by ELISA. Results: Flour challenge increased the percentage of eosinophils in sputum samples. Asthmatic reactions induced by flour were associated with a significant increase in the sputum level of MMP-9 (p = 0.05), but not in the levels of MMP-2, MMP-7, MMP-13, TIMP-1 and TIMP-2. Sputum levels of MMP-9 measured after flour challenge were nearly significantly correlated (r = 0.67; p = 0.06) with the maximal fall in FEV(1) observed during the asthmatic reaction, but they did not correlate with the number of neutrophils (r = 0.18; p = 0.7) and eosinophils (r = 0.55; p = 0.2). Conclusions: This study showed that MMP-9 increases in sputum samples from sensitized occupational asthma patients after SIC with flour

Sea star-inspired recombinant adhesive proteins self-assemble and adsorb on surfaces in aqueous environments to form cytocompatible coatings

peer reviewedSea stars adhere to various underwater substrata using an efficient protein-based adhesive secretion. The protein Sfp1 is a major component of this secretion. In the natural glue, it is cleaved into four subunits (Sfp1 Alpha, Beta, Delta and Gamma) displaying specific domains which mediate protein-protein or protein-carbohydrate interactions. In this study, we used the bacterium E. coli to produce recombinantly two fragments of Sfp1 comprising most of its functional domains: the C-terminal part of the Beta subunit (rSfp1 Beta C-term) and the Delta subunit (rSfp1 Delta). Using native polyacrylamide gel electrophoresis and size exclusion chromatography, we show that the proteins self-assemble and form oligomers and aggregates in the presence of NaCl. Moreover, they adsorb onto glass and polystyrene upon addition of Na+ and/or Ca2+ ions, forming homogeneous coatings or irregular meshworks, depending on the cation species and concentration. We show that coatings made of each of the two proteins have no cytotoxic effects on HeLa cells and even increase their proliferation. We propose that the Sfp1 recombinant protein coatings are valuable new materials with potential for cell culture or biomedical applications.Production and testing of recombinant sea star adhesive proteins - Fédération Wallonie Bruxelle