Maladie de décompression : des mécanismes physiopathologiques au test diagnostique

Decompression sickness is a well-known issue in the SCUBA diving world that can lead to serious health problems if it is not treated as soon as possible. It is caused by the pressure variation occurring when the divers’ depth changes underwater. It Rapid diagnostic tests (RTD) widely used nowadays not only by healthcare professionals but also patients themselves would be a true asset for divers. However, this calls for a better understanding of the physiopathology of decompression sickness as it is yet to be solved, making tough the development of an efficient RTD. This work describes decompression sickness and then focuses on the physiopathological pathways uncovered by scientists, that would allow every diver to have a RTD on their first aid kit.La maladie de décompression est une menace qui plane sur les amateurs de plongée sous-marine. Elle met en cause les variations de pression qui surviennent pendant le séjour en immersion et peut avoir des conséquences très graves si elle n’est pas traitée dans les plus brefs délais. A l’ère des tests diagnostiques rapides (TDR) qui permettent aux praticiens, mais aussi dans certains cas aux patients eux-mêmes d'orienter immédiatement un diagnostic, un tel outil serait un véritable atout pour les plongeurs. Cependant les mécanismes physiopathologiques sous-jacents à la maladie de décompression restent à ce jour assez vagues et rendent ardue la conception d'un TDR. L'objectif de cette thèse consiste à décrire la maladie de décompression afin d'évoquer ensuite les différentes pistes avancées pour élucider les mécanismes physiopathologiques et pouvoir envisager la conception d'un TDR que les plongeurs pourraient embarquer dans leur trousse de secours

Microplastic dispersal behavior in a novel overhead stirring aqueous exposure system

Using nominal dose metrics to describe exposure conditions in laboratory-based microplastic uptake and effects studies may not adequately represent the true exposure to the organisms in the test system, making data interpretation challenging. In the current study, a novel overhead stirring method using flocculators was assessed for maintaining polystyrene (PS) microbeads (Ø10.4 μm; 1.05 g cm−3) in suspension in seawater during 24 h and then compared with static and rotational exposure setups. Under optimized conditions, the system was able to maintain 59% of the initial PS microbeads in suspension after 24 h, compared to 6% using a static system and 100% using a rotating plankton wheel. Our findings document for the first time that overhead stirring as well as other, commonly used exposure systems (static) are unable to maintain constant microplastic exposure conditions in laboratory setups whereas rotation is very effective. This suggests toxicological studies employing either static or overhead stirring systems may be greatly overestimating the true microplastic exposure conditions.publishedVersio

Microplastic dispersal behavior in a novel overhead stirring aqueous exposure system

Using nominal dose metrics to describe exposure conditions in laboratory-based microplastic uptake and effects studies may not adequately represent the true exposure to the organisms in the test system, making data interpretation challenging. In the current study, a novel overhead stirring method using flocculators was assessed for maintaining polystyrene (PS) microbeads (Ø10.4 μm; 1.05 g cm−3) in suspension in seawater during 24 h and then compared with static and rotational exposure setups. Under optimized conditions, the system was able to maintain 59% of the initial PS microbeads in suspension after 24 h, compared to 6% using a static system and 100% using a rotating plankton wheel. Our findings document for the first time that overhead stirring as well as other, commonly used exposure systems (static) are unable to maintain constant microplastic exposure conditions in laboratory setups whereas rotation is very effective. This suggests toxicological studies employing either static or overhead stirring systems may be greatly overestimating the true microplastic exposure conditions

Microplastic dispersal behavior in a novel overhead stirring aqueous exposure system

Using nominal dose metrics to describe exposure conditions in laboratory-based microplastic uptake and effects studies may not adequately represent the true exposure to the organisms in the test system, making data interpretation challenging. In the current study, a novel overhead stirring method using flocculators was assessed for maintaining polystyrene (PS) microbeads (Ø10.4 μm; 1.05 g cm−3) in suspension in seawater during 24 h and then compared with static and rotational exposure setups. Under optimized conditions, the system was able to maintain 59% of the initial PS microbeads in suspension after 24 h, compared to 6% using a static system and 100% using a rotating plankton wheel. Our findings document for the first time that overhead stirring as well as other, commonly used exposure systems (static) are unable to maintain constant microplastic exposure conditions in laboratory setups whereas rotation is very effective. This suggests toxicological studies employing either static or overhead stirring systems may be greatly overestimating the true microplastic exposure conditions