Selected scientific publications on diving medicine and physiology.
Saturation divers are exposed to elevated partial pressure of oxygen (ppO2) in their hyperbaric work environment. Experimental studies indicate that oxygen transport is altered, and we have previously reported a drop in hematocrit and extensive downregulation of genes involved in blood oxygen transport capacity after decompression from professional saturation diving. Here we investigate the initial period of hematological adjustment back to normobaric air after professional saturation diving. Erythropoietin (EPO) and hemoglobin (Hb) were measured in blood from 13 divers at two time-points after saturation assignments lasting up to 4 weeks; first immediately after decompression and again 24 h later. Pre-dive levels defined baselines.Read more
Oxygenation conditions are crucial for growth and tumor progression. Recent data suggests a decrease in cancer cell proliferation occurring after exposure to normobaric hyperoxia. Those changes are associated with fractal dimension. The purpose of this research was to study the impact of hyperoxia on apoptosis and morphology of leukemia cell lines. Two hematopoietic lymphoid cancer cell lines (a T-lymphoblastoid line, JURKAT and a B lymphoid line, CCRF-SB) were tested under conditions of normobaric hyperoxia (FiO2 > 60%, ± 18h) and compared to a standard group (FiO2 = 21%). We tested for apoptosis using a caspase-3 assay.Read more
Scuba divers with patent foramen ovale (PFO) may be at risk for paradoxical nitrogen gas emboli when performing maneuvers that cause a rebound blood loading to the right atrium. We measured the rise and fall in intrathoracic pressure (ITP) during various maneuvers in 15 divers. The tests were standard isometric exercises (control), forceful coughing, knee bend (with and without respiration blocked), and Valsalva maneuver (maximal, gradually increased to reach control ITP, and as performed by divers to equalize middle ear pressure). All the maneuvers, as well as the downward slope of ITP at the release phase, were related to the control value.Read more
Vascular gas emboli (VGE) start forming during the degassing of tissues in the decompression (ascent) phase of the dive when bubble precursors (micronuclei) are triggered to growth. The precise formation mechanism of micronuclei is still debated, with formation sites in facilitating regions with surfactants, hydrophobic surfaces or crevices. Ho wever, significant inter-subject variability to VGE exists for the same diving exposure and VGE may even be reduced with a single pre-dive intervention. The precise link between VGE and endothelial dysfunction observed post dive remains unclear and a nitric oxide (NO) mechanism has been hypothesized.Read more
L'eau est une matière plurielle et ambivalente. Symboliquement associée à la purification, cause régulière de multiples ravages humains et écologiques, elle est aussi devenue un vaste terrain de jeu, d'expériences corporelles, d'immersions en tous genres. Retenir son souffle pour aller loin, profond, ou simplement rester longtemps immergé, passionne des pratiquants toujours plus nombreux. Il s'agit bien souvent de « se fondre » dans le milieu, repousser ses limites et surtout se reconnecter avec soi-même, explorer son propre corps et se sentir « bien ». L'apprentissage de l'apnée révèle les capacités d'adaptation du corps humain, actualisant des ressources inédites.Read more
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