OBJECTIVES: Vasodilation of the peripheral arteries during reactive hyperaemia depends in part on release of nitric oxide from endothelial cells. Previous studies mainly employed a fingertip tonometric device to derive pulse wave amplitude (PWA) and PWA hyperaemic changes. An alternative approach is based on photoplethysmography (PPG). We sought to evaluate the correlates of digital PPG PWA hyperaemic responses as a measure of peripheral vascular function...Lees verder
Decompression sickness (DCS) is a systemic disorder, assumed due to gas bubbles, but additional factors are likely to play a role. Circulating microparticles (MPs)--vesicular structures with diameters of 0.1-1.0 μm--have been implicated, but data in human divers have been lacking...Lees verder
Post decompression records in echocardiography are considered to detect micro bubbles and to survey unexplained decompression sickness which is commonly examined by standardized methods such as dive computers and tables. In this study, existent bubbles are detected on transthoracic echicardiografic frames recorded after recreational diving. Bubble detection is performed by Artificial Neural Networks which are trained using bubbles with different morphologies. We showed that bubbles would be detected on four cardiac chambers without image segmentation.Lees verder
Bubble formation during scuba diving might induce decompression sickness. This prospective randomised and double-blind study included 108 advanced recreational divers (38 females). Fifty-four pairs of divers, 1 breathing air and the other breathing nitrox28 undertook a standardised dive (24 ± 1 msw; 62 ± 5min) in the Red Sea. Venous gas bubbles were counted (Doppler) 30-<45 min (early) and 45-60 min (late) post-dive at jugular, subclavian and femoral sites. Only 7% (air) vs. 11% (air28®) (n.s.) were bubble-free after a dive. Independent of sampling time and breathing gas, there were more bubbles in the jugular than in the femoral vein. More bubbles were counted in the air-group than in the air28-group (pooled vein: early: 1845 vs. 948; P = 0.047, late: 1817 vs. 953; P = 0.088). The number of bubbles was sex-dependent. Lastly, 29% of female air divers but only 14% of male divers were bubble-free (P = 0.058). Air28® helps to reduce venous gas emboli in recreational divers. The bubble number depended on the breathing gas, sampling site and sex. Thus, both exact reporting the dive and in particular standardising sampling characteristics seem mandatory to compare results from different studies to further investigate the hitherto incoherent relation between inert gas bubbles and DCS.Lees verder
Several illnesses such as paradoxical embolism, decompression sickness, migraine and cerebral ischemia are characterized by bubbles which might cross the septum wall between left and right atrium. In this study, we aimed to detect bubbles on echocardiographic frames which are segmented automatically using Snakes method. In recent studies, analyzes are done on fixed ROIs and PFO grading as well. We conclude that our approach would give more accurate results for bubble detection and counting by taking account into entire left atrium (LA) areas.Lees verder
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