Selected scientific publications on diving medicine and physiology.
2018 Apr 3
Variability in circulating gas emboli after a same scuba diving exposure
Papadopoulou V., Germonpré P., Cosgrove D., Eckersley RJ., Dayton PA., Obeid G., Boutros A., Tang MX., Theunissen S., Balestra C.
A reduction in ambient pressure or decompression from scuba diving can result in ultrasound-detectable venous gas emboli (VGE). These environmental exposures carry a risk of decompression sickness (DCS) which is mitigated by adherence to decompression schedules; however, bubbles are routinely observed for dives well within these limits and significant inter-personal variability in DCS risk exists. Here, we assess the variability and evolution of VGE for 2 h post-dive using echocardiography, following a standardized pool dive in calm warm conditions.
Increasing Oxygen Partial Pressures Induce a Distinct Transcriptional Response in Human PBMC: A Pilot Study on the “Normobaric Oxygen Paradox”
Fratantonio D, Virgili F, Zucchi A, Lambrechts K, Latronico T, Lafère P, Germonpré P, Balestra C.
The term “normobaric oxygen paradox” (NOP), describes the response to the return to normoxia after a hyperoxic event, sensed by tissues as oxygen shortage, and resulting in up-regulation of the Hypoxia-inducible factor 1α (HIF-1α) transcription factor activity. The molecular characteristics of this response have not been yet fully characterized. Herein, we report the activation time trend of oxygen-sensitive transcription factors in human peripheral blood mononuclear cells (PBMCs) obtained from healthy subjects after one hour of exposure to mild (MH), high (HH) and very high (VHH) hyperoxia, corresponding to 30%, 100%, 140% O2, respectively.
Impaired Attentional Processing During Parabolic Flight
Friedl-Werner A, Machado M-L, Balestra C, Liegard Y, Philoxene B, Brauns K, Stahn AC, Hitier M, Besnard S.
Previous studies suggest that altered gravity levels during parabolic flight maneuvers affect spatial updating. Little is known about the impact of the experimental setting and psychological stressors associated with parabolic flight experiments on attentional processes. To address this gap, we investigated the level of alertness, selective and sustained attention in 1 and 0 g using a Go/No-Go Continuous Performance Task. We also identified several parameters associated with the experimental set-up of a parabolic flight that could be expected to affect attentional processing.
Feasibility of Detecting Brain Areas Involved in Extreme Breath-Hold Diving
Jissendi-Tchofo P, Jdaoudi Y, Germonpré P, Brizzolari A, Musimu P, Balestra C.
We report Blood Oxygen Level Dependent (BOLD) signal changes recorded in the brain of an elite breath-hold diver during voluntary dry long breath-hold by means of fMRI. An independent component analysis (ICA) method was applied to extract brain areas that are putatively involved in the apnea process network. We discuss the hypothesis that these BOLD signal variations express the functional adaptive diving response under long apnea at rest. This is a preliminary report, which results are promising for large series investigations.
A fully automated method for late ventricular diastole frame selection in post-dive echocardiography without ECG gating
Markley E, Le DQ, Germonpre P, Balestra C, Tillmans F, Denoble P, Freiberger JJ, Moon RE, Dayton PA, Papadopoulou V.
Venous gas emboli (VGE) are often quantified as a marker of decompression stress on echocardiograms. Bubble-counting has been proposed as an easy to learn method, but remains time-consuming, rendering large dataset analysis impractical. Computer automation of VGE counting following this method has therefore been suggested as a means to eliminate rater bias and save time. A necessary step for this automation relies on the selection of a frame during late ventricular diastole (LVD) for each cardiac cycle of the recording. Since electrocardiograms (ECG) are not always recorded in field experiments, here we propose a fully automated method for LVD frame selection based on regional intensity minimization.
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