Bubbles, microparticles, and neutrophil activation: changes with exercise level and breathing gas during open-water SCUBA diving

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) would alter annexin V-positive microparticle (MP) production and size changes and neutrophil activation, as well as their relationships to intravascular bubble formation. Twenty-four divers followed a uniform dive profile to 18 m of sea water breathing air or 22.5 m breathing 32% oxygen/68% nitrogen for 47 min, either swimming with moderately heavy exertion underwater or remaining stationary at depth. Blood was obtained pre- and at 15 and 120 min postdive. Intravascular bubbles were quantified by transthoracic echocardiography postdive at 20-min intervals for 2 h. There were no significant differences in maximum bubble scores among the dives. MP number increased 2.7-fold, on average, within 15 min after each dive; only the air-exertion dive resulted in a significant further increase to 5-fold over baseline at 2 h postdive. Neutrophil activation occurred after all dives. For the enriched air nitrox stationary at depth dive, but not for other conditions, the numbers of postdive annexin V-positive particles above 1 μm in diameter were correlated with intravascular bubble scores (correlation coefficients ∼0.9, P < 0.05). We conclude that postdecompression relationships among bubbles, MPs, platelet-neutrophil interactions, and neutrophil activation appear to exist, but more study is required to improve confidence in the associations.

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Microparticle production, neutrophil activation, and intravascular bubbles following open-water SCUBA diving

Journal of Applied Physiology ◽

10.1152/japplphysiol.01305.2011 ◽

2012 ◽

Vol 112 (8) ◽

pp. 1268-1278 ◽

Cited By ~ 62

Author(s):

Stephen R. Thom ◽

Tatyana N. Milovanova ◽

Marina Bogush ◽

Veena M. Bhopale ◽

Ming Yang ◽

...

Keyword(s):

Sea Water ◽

Bubble Formation ◽

Annexin V ◽

Scuba Diving ◽

Open Water ◽

Surface Expression ◽

Neutrophil Activation ◽

Positive Correlations ◽

The Impact ◽

Neutrophil Surface

The goal of this study was to evaluate annexin V-positive microparticles (MPs) and neutrophil activation in humans following decompression from open-water SCUBA diving with the hypothesis that changes are related to intravascular bubble formation. Sixteen male volunteer divers followed a uniform profile of four daily SCUBA dives to 18 m of sea water for 47 min. Blood was obtained prior to and at 80 min following the first and fourth dives to evaluate the impact of repetitive diving, and intravascular bubbles were quantified by trans-thoracic echocardiography carried out at 20-min intervals for 2 h after each dive. MPs increased by 3.4-fold after each dive, neutrophil activation occurred as assessed by surface expression of myeloperoxidase and the CD18 component of β2-integrins, and there was an increased presence of the platelet-derived CD41 protein on the neutrophil surface indicating interactions with platelet membranes. Intravascular bubbles were detected in all divers. Surprisingly, significant inverse correlations were found among postdiving bubble scores and MPs, most consistently at 80 min or more after the dive on the fourth day. There were significant positive correlations between MPs and platelet-neutrophil interactions after the first dive and between platelet-neutrophil interactions and neutrophil activation documented as an elevation in β2-integrin expression after the fourth dive. We conclude that MPs- and neutrophil-related events in humans are consistent with findings in an animal decompression model. Whether there are causal relationships among bubbles, MPs, platelet-neutrophil interactions, and neutrophil activation remains obscure and requires additional study.

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Ascorbic acid supplementation diminishes microparticle elevations and neutrophil activation following SCUBA diving

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00155.2015 ◽

2015 ◽

Vol 309 (4) ◽

pp. R338-R344 ◽

Cited By ~ 9

Author(s):

Ming Yang ◽

Otto F. Barak ◽

Zeljko Dujic ◽

Dennis Madden ◽

Veena M. Bhopale ◽

...

Keyword(s):

Ascorbic Acid ◽

Sea Water ◽

Annexin V ◽

Scuba Diving ◽

Open Water ◽

Face Mask ◽

Neutrophil Activation ◽

Acid Supplementation ◽

Male Subjects ◽

Ascorbic Acid Supplementation

Predicated on evidence that diving-related microparticle generation is an oxidative stress response, this study investigated the role that oxygen plays in augmenting production of annexin V-positive microparticles associated with open-water SCUBA diving and whether elevations can be abrogated by ascorbic acid. Following a cross-over study design, 14 male subjects ingested placebo and 2–3 wk later ascorbic acid (2 g) daily for 6 days prior to performing either a 47-min dive to 18 m of sea water while breathing air (∼222 kPa N2/59 kPa O2) or breathing a mixture of 60% O2/balance N2 from a tight-fitting face mask at atmospheric pressure for 47 min (∼40 kPa N2/59 kPa O2). Within 30 min after the 18-m dive in the placebo group, neutrophil activation, and platelet-neutrophil interactions occurred, and the total number of microparticles, as well as subgroups bearing CD66b, CD41, CD31, CD142 proteins or nitrotyrosine, increased approximately twofold. No significant elevations occurred among divers after ingesting ascorbic acid, nor were elevations identified in either group after breathing 60% O2. Ascorbic acid had no significant effect on post-dive intravascular bubble production quantified by transthoracic echocardiography. We conclude that high-pressure nitrogen plays a key role in neutrophil and microparticle-associated changes with diving and that responses can be abrogated by dietary ascorbic acid supplementation.

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Beneficial effect of enriched air nitrox on bubble formation during scuba diving. An open-water study

Journal of Sports Sciences ◽

10.1080/02640414.2017.1326617 ◽

2017 ◽

Vol 36 (6) ◽

pp. 605-612 ◽

Cited By ~ 1

Author(s):

Anne-Kathrin Brebeck ◽

Andreas Deussen ◽

Ursula Range ◽

Costantino Balestra ◽

Sinclair Cleveland ◽

...

Keyword(s):

Beneficial Effect ◽

Bubble Formation ◽

Scuba Diving ◽

Open Water

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Ice Conditions of an Arctic Polynya: North Water in Winter

Journal of Glaciology ◽

10.1017/s0022143000012089 ◽

1986 ◽

Vol 32 (112) ◽

pp. 383-390 ◽

Cited By ~ 35

Author(s):

Konrad Steffen

Keyword(s):

Sea Water ◽

Surface Condition ◽

Open Water ◽

Sea Surface ◽

Aerial Images ◽

The Arctic ◽

The North ◽

North Water ◽

Ice Conditions ◽

Fast Ice

AbstractThe surface condition of the North Water was investigated during two winters (i.e. the three polynyas: Smith Sound polynya, Lady Ann Strait polynya, and Barrow Strait polynya). Since no detailed information was available on ice conditions and the extent of open water during winter, radiometric temperature measurements of the sea surface had to be taken along a flight line of 2650 km from an altitude of 300 m. From November to March 1978-79 and 1980-81, 14 remote-sensing flights were carried out. On the basis of the radiometric measurements, the following ice types were identified: ice-free, dark nilas, light nilas, grey ice, grey-white ice, and white ice. A comparison between the thermal and the visual ice classification (the latter being based on grey tones of the aerial images) showed a deviation of 3%. The analysis showed that in November, December, and January more than 50% of the Smith Sound polynya was covered by young ice, nilas, and ice-free, whereas in February and March white ice was dominant. Moreover, it was found that the two polynyas in Smith Sound and Lady Ann Strait were much smaller than previously believed. In Barrow Strait, a semi-permanent polynya was observed in the winter of 1980-81. The occurrence of polynyas in Barrow Strait seems to be connected with the location of the fast-ice edge. On the basis of the calculated ice-type distribution and heat-flux rates for different ice types, an energy loss of 178 W m-2was found on the surface of the Smith Sound polynya due to open water and thin ice for the winter months November to March. Compared with other ice-covered sea surfaces in the Arctic, the heat release by the sea-water in the Smith Sound polynya is about 100 W m-2larger.

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Intramicroparticle nitrogen dioxide is a bubble nucleation site leading to decompression-induced neutrophil activation and vascular injury

Journal of Applied Physiology ◽

10.1152/japplphysiol.01386.2012 ◽

2013 ◽

Vol 114 (5) ◽

pp. 550-558 ◽

Cited By ~ 23

Author(s):

Stephen R. Thom ◽

Ming Yang ◽

Veena M. Bhopale ◽

Tatyana N. Milovanova ◽

Marina Bogush ◽

...

Keyword(s):

Nitrogen Dioxide ◽

Ex Vivo ◽

Ambient Pressure ◽

Annexin V ◽

Nucleation Site ◽

Bubble Nucleation ◽

Neutrophil Activation ◽

Inert Gases ◽

Wild Type ◽

Inos Inhibitor

Inert gases diffuse into tissues in proportion to ambient pressure, and when pressure is reduced, gas efflux forms bubbles due to the presence of gas cavitation nuclei that are predicted based on theory but have never been characterized. Decompression stress triggers elevations in number and diameter of circulating annexin V-coated microparticles (MPs) derived from vascular cells. Here we show that ∼10% MPs from wild-type (WT) but not inflammatory nitric oxide synthase-2 (iNOS) knockout (KO) mice increase in size when exposed to elevated air pressure ex vivo. This response is abrogated by a preceding exposure to hydrostatic pressure, demonstrating the presence of a preformed gas phase. These MPs have lower density than most particles, 10-fold enrichment in iNOS, and generate commensurately more reactive nitrogen species (RNS). Surprisingly, RNS only slowly diffuse from within MPs unless particles are subjected to osmotic stress or membrane cholesterol is removed. WT mice treated with iNOS inhibitor and KO mice exhibit less decompression-induced neutrophil activation and vascular leak. Contrary to injecting naïve mice with MPs from wild-type decompressed mice, injecting KO MPs triggers fewer proinflammatory events. We conclude that nitrogen dioxide is a nascent gas nucleation site synthesized in some MPs and is responsible for initiating postdecompression inflammatory injuries.

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Coastal Tidal Effects on Industrial Thermal Plumes in Satellite Imagery

Remote Sensing ◽

10.3390/rs11182132 ◽

2019 ◽

Vol 11 (18) ◽

pp. 2132 ◽

Cited By ~ 2

Author(s):

Agnieszka Faulkner ◽

Claire E. Bulgin ◽

Christopher J. Merchant

Keyword(s):

Sea Water ◽

Open Water ◽

Ecological Impacts ◽

Coastal Environments ◽

Tide Gauges ◽

Tidal Effects ◽

Thermal Plumes ◽

Different Types ◽

Coastal Features ◽

The Uk

Coastal tidal effects on thermal plumes are investigated, exploiting remote sensing of two major coastal industrial installations. The installations use sea water as a coolant, which is then released back into coastal environments at a higher-than-ambient temperature, allowing the plume to be delineated from the ambient waters. Satellite-based thermal sensors observing the Earth at spatial resolutions of 90 and 100 m are used. It is possible to identify coastal features and thermal spatial distributions. This paper presents coastal tidal effects on detected plumes for two case studies: an intertidal embayment and open water exposure, both on the coast of the UK. We correlated the behaviours of thermal plumes using remotely sensed high resolution thermal imagery with tidal phases derived from tide gauges. The results show very distinct behaviours for the flood and ebb tides. The detected surface plume location was dependent on flow switching direction for the different types of tide. The detected surface area was dependent on the strength of the currents, with the largest area observed during the strongest currents. Understanding the dispersion of the plume is essential to influence understanding of any potential ecological impacts.

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Dual Frequency Radar Ice and Snow Signatures

Journal of Glaciology ◽

10.3189/s0022143000008340 ◽

1983 ◽

Vol 29 (102) ◽

pp. 286-295

Author(s):

R. D. Ketchum

Keyword(s):

Sea Ice ◽

Sea Water ◽

Open Water ◽

Good Choice ◽

Signal Loss ◽

Dual Frequency ◽

X Band ◽

Radar Imagery ◽

High Backscatter ◽

L Band

AbstractDual frequency (X-band and L-band) synthetic-aperture radar imagery of sea ice is examined to show the differences between the bands and their complementary nature for resolving ambiguities in interpretation. High backscatter at X-band from visibly smooth thin ice is not observed at L-band. One hypothesis is that the high X-band backscatter may be caused by a reflective layer at the snow/ice interface. A second hypothesis is that the high X-band backscatter may be caused by moisture in the snow. A third hypothesis states that the phenomenon may be due to snow flowers. High backscatter at L-band is observed for slush on open water. The return is very weak at X-band, thus allowing distinction of slush by comparing L-band and X-band images. High intensity, but only partial returns from icebergs at L-band have been observed. The hypothesis is that internal iceberg/sea-water reflections are occurring. Some signals are directed away from the antenna, other reinforced signals are returned, producing very bright images. Occasionally, time-delayed signals are returned causing a false image at far range from the iceberg. The conclusion is that L-band is a poor choice for studies of iceberg distribution and size, but a good choice for iceberg detection because of the high reinforced returns from many icebergs and the low return from the adjacent sea ice. The penetration and subsequent signal loss of L-band in glacial ice, when compared to high X-band returns, may be useful to map glacierized land masses.

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Venous gas bubble formation and decompression risk after scuba diving in persons with chronic spinal cord injury and able-bodied controls

Spinal Cord ◽

10.1038/sc.2008.44 ◽

2008 ◽

Vol 46 (11) ◽

pp. 743-747 ◽

Cited By ~ 3

Author(s):

T Breskovic ◽

P Denoble ◽

I Palada ◽

A Obad ◽

Z Valic ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Bubble Formation ◽

Scuba Diving ◽

Gas Bubble ◽

Chronic Spinal Cord Injury ◽

Cord Injury

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Exercise after SCUBA diving increases the incidence of arterial gas embolism

Journal of Applied Physiology ◽

10.1152/japplphysiol.00029.2013 ◽

2013 ◽

Vol 115 (5) ◽

pp. 716-722 ◽

Cited By ~ 13

Author(s):

Dennis Madden ◽

Mislav Lozo ◽

Zeljko Dujic ◽

Marko Ljubkovic

Keyword(s):

Transthoracic Echocardiography ◽

Patent Foramen Ovale ◽

Maximal Exercise ◽

Scuba Diving ◽

Foramen Ovale ◽

Gas Embolism ◽

Heavy Equipment ◽

Pulmonary Microcirculation ◽

The Right ◽

Ergometry Test

Arterialization of gas bubbles after decompression from scuba diving has traditionally been associated with pulmonary barotraumas or cardiac defects, such as the patent foramen ovale. Recent studies have demonstrated the right-to-left passage of bubbles through intrapulmonary arterial-venous anastamoses (IPAVA) that allow blood to bypass the pulmonary microcirculation. These passages open up during exercise, and the aim of this study is to see if exercise in a postdiving period increases the incidence of arterialization. After completing a dive to 18 m for 47 min, patent foramen ovale-negative subjects were monitored via transthoracic echocardiography, within 10 min after surfacing, for bubble score at rest. Subjects then completed an incremental cycle ergometry test to exhaustion under continuous transthoracic echocardiography observation. Exercise was suspended if arterialization was observed and resumed when the arterialization cleared. If arterialization was observed a second time, exercise was terminated, and oxygen was administered. Out of 23 subjects, 3 arterialized at rest, 12 arterialized with exercise, and 8 did not arterialize at all even during maximal exercise. The time for arterialization to clear with oxygen was significantly shorter than without. Exercise after diving increased the incidence of arterialization from 13% at rest to 52%. This study shows that individuals are capable of arterializing through IPAVA, and that the intensity at which these open varies by individual. Basic activities associated with SCUBA diving, such as surface swimming or walking with heavy equipment, may be enough to allow the passage of venous gas emboli through IPAVA.

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