[abstract]BUBBLES, MICROPARTICLES AND NEUTROPHIL ACTIVATION: CHANGES WITH EXERCISE LEVEL AND BREATHING GAS DURING OPEN-WATER SCUBA DIVING

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[abstract]BUBBLES, MICROPARTICLES AND NEUTROPHIL ACTIVATION: CHANGES WITH EXERCISE LEVEL AND BREATHING GAS DURING OPEN-WATER SCUBA DIVING

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Title: [abstract]BUBBLES, MICROPARTICLES AND NEUTROPHIL ACTIVATION: CHANGES WITH EXERCISE LEVEL AND BREATHING GAS DURING OPEN-WATER SCUBA DIVING
Author: Thom SR; Milovanova TN; Bogush M; Yang M; Bhopale VM; Pollock NW; Ljubkovic M; Denoble PJ; Madden D; Lozo M; Dujic Z
Abstract: INTRODUCTION: Decompression-induced elevations in circulating microparticles (MPs) occur in animals and humans after simulated or bona fide underwater diving. The cause-effect relationships among MPs, bubbles and decompression stress are more complex than initially considered because a subset of MPs can serve as gas nucleation sites. The study goal was to evaluate responses in humans following decompression from open-water scuba diving, with the hypothesis that exertion underwater and use of a breathing mixture containing more oxygen and less nitrogen (enriched air nitrox, EAN) would alter annexin V-positive MPs production and size changes and neutrophil activation as well as their relationships to intravascular bubble formation. METHODS: Twenty-four divers, four female, participated in the study. Four conditions were tested as repeated measures: uniform dive profiles to 18 meters of sea water (msw) and 22.5 msw breathing air or an equivalent air depth 32 percent oxygen/68 percent nitrogen EAN, respectively, for 47 minutes, with continuous moderately heavy swimming exercise or stationary rest at depth. Venous blood was obtained prior to and at 15 and 120 minutes post-dive for MPs and neutrophil analysis. Intravascular bubbles were quantified by transthoracic echocardiography at 20 minute intervals for two hours post-dive. RESULTS: There were no significant differences in maximum bubble scores among the dives. MPs number increased 2.7-fold on average within 15 minutes after each dive; only the air-exertion dive resulted in a significant further increase to 5-fold over baseline at two hours post-dive. Neutrophil activation occurred after all dives. For the EAN-rest dive, but not for other conditions, the numbers of post-dive annexin V-positive particles above 1 µm in diameter were correlated with intravascular bubble scores (correlation coefficients ~0.9, p less than 0.05). CONCLUSION: We conclude that post-decompression relationships among bubbles, MPs, platelet-neutrophil interactions and neutrophil activation appear to exist, but more study is required to improve confidence in the associations.
Description: Undersea and Hyperbaric Medicine : Journal of the Undersea and Hyperbaric Medical Society, Inc.
URI: http://archive.rubicon-foundation.org/10620
Date: 2013

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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