Adv Exp Med Biol
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Tissue oxygenation during exercise measured with NIRS: reproducibility and influence of wavelengths.
Near-infrared spectroscopy (NIRS) is widely used for the measurement of skeletal muscle oxygenation during exercise as it reflects muscle metabolism, and most studies report a large variability between subjects. Here we assess the data quality of tissue oxygen saturation (SO2) and oxygenated (oxyHb) and deoxygenated (deoxyHb) haemoglobin concentrations recorded during an incremental cycling protocol in nine healthy volunteers. ⋯ We found that the inter-subject variation in SO2 (standard deviation ≈ 6 %) was considerably larger than the reproducibility (≈ 1.5 %) both for the same-day and different-day tests. The reproducibility of changes in SO2 was better than 1 %.
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We report the use of a novel hybrid near-infrared spectrometer for the measurement of optical scattering, pathlength and chromophore concentration in critically ill patients with brain injury. Ten mechanically ventilated patients with acute brain injury were studied. In addition to standard neurointensive care monitoring, middle cerebral artery flow velocity, brain lactate-pyruvate ratio (LPR) and brain tissue oxygen tension were monitored. ⋯ NBH induced significant changes in the concentrations of oxyhaemoglobin, deoxyhaemoglobin and oxidised-reduced cytochrome c oxidase; these were accompanied by a corresponding reduction in brain LPR and increase in brain tissue oxygen tension. No significant change in optical scattering or pathlength was observed. These results suggest that the measurement of chromophore concentration in the injured brain is not confounded by changes in optical scattering or pathlength and that NBH induces an increase in cerebral aerobic metabolism.
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The aim of this study was to investigate lung function in patients with gastro-esophageal reflux disease (GERD) who present respiratory symptoms suggestive of the possibility of co-morbid asthma. The study encompassed 20 patients (9 women and 11 men; age range from 11 to 68 years) diagnosed with GERD and presenting with chronic cough and other non-specific periodic respiratory complaints. The control group consisted of closely gender and age-matched 20 subjects without any gastrointestinal or respiratory symptoms. ⋯ There were, however, decreases in forced expired volume in 1 s, forced vital capacity, and in maximal instantaneous forced expiratory flows in the GERD patients compared with the healthy subjects. We conclude that cough accompanying GERD is unlikely to be associated with the presence of co-morbid asthma, but rather suggests a mild airway inflammation developing as a sequel of GERD. The corollary is that chronic cough should prompt physician's attention to consider diagnostic work-up toward the possibility of GERD.
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Sarcoidosis is a granulomatous multiorgan diseases with an unknown etiology, with the predominant lung involvement. Immunosuppressive agents such as corticosteroids, methotrexate, azathioprinum, ciclosporinum A, chlorambucil, cyclophosphamide, hydroxychlorochinum, indomethacin, pentoxyfillinum, thalidomide, leflunomidum, and adalimumab, or infliximab have been used in its treatment. It should be emphasized that the Summary of Products Characteristics (SPC) of these drugs does not specifically recommend their use in the therapy for sarcoidosis. ⋯ The doctrine of law assumes that the off-label use constitutes a medical experiment. Therefore, the commencement of therapy with such drugs requires patients' informed consent, which must be kept along with other medical records. Insufficient knowledge of the legal regulations may result in civil and professional liability of a physician supervising the therapy of a sarcoidosis patient, especially in case of adverse effects.
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We describe the extension of a computational model of blood flow and metabolism in the piglet brain to investigate changes in neonatal intracellular brain pH during hypoxia-ischemia (HI). The model is able to simulate near-infrared spectroscopy (NIRS) and magnetic resonance spectroscopy (MRS) measurements obtained from HI experiments conducted in piglets. We adopt a method of using (31)P-MRS data to estimate of intracellular pH and compare measured pH and oxygenation with their modelled counterparts. We show that both NIRS and MRS measurements are predicted well in the new version of the model.