Continuous measurement of cerebral oxygen saturation (rSO 2) for assessment of cardiovascular status during hemorrhagic shock in a swine model

Background: Early trauma care is dependent on subjective assessments and sporadic vital sign assessments. We hypothesized that near-infrared spectroscopy-measured cerebral oxygenation (regional oxygen saturation [rSO 2]) would provide a tool to detect cardiovascular compromise during active hemorrhage. We compared rSO 2 with invasively measured mixed venous oxygen saturation (SvO2), mean arterial pressure (MAP), cardiac output, heart rate, and calculated pulse pressure. Methods: Six propofol-anesthetized instrumented swine were subjected to a fixed-rate hemorrhage until cardiovascular collapse. rSO 2 was monitored with noninvasively measured cerebral oximetry; SvO2 was measured with a fiber optic pulmonary arterial catheter. As an assessment of the time responsiveness of each variable, we recorded minutes from start of the hemorrhage for each variable achieving a 5%, 10%, 15%, and 20% change compared with baseline. Results: Mean time to cardiovascular collapse was 35 minutes ± 11 minutes (54 ± 17% total blood volume). Cerebral rSO 2 began a steady decline at an average MAP of 78 mm Hg ± 17 mm Hg, well above the expected autoregulatory threshold of cerebral blood flow. The 5%, 10%, and 15% decreases in rSO 2 during hemorrhage occurred at a similar times to SvO2, but rSO 2 lagged 6 minutes behind the equivalent percentage decreases in MAP. There was a higher correlation between rSO 2 versus MAP (R =0.72) than SvO2 versus MAP (R =0.55). Conclusions: Near-infrared spectroscopy- measured rSO 2 provided reproducible decreases during hemorrhage that were similar in time course to invasively measured cardiac output and SvO2 but delayed 5 to 9 minutes compared with MAP and pulse pressure. rSO 2 may provide an earlier warning of worsening hemorrhagic shock for prompt interventions in patients with trauma when continuous arterial BP measurements are unavailable. © 2012 Lippincott Williams & Wilkins.

Ablation of the ability to control the right-to-left cardiac shunt does not affect oxygen uptake, specific dynamic action or growth in the rattlesnake Crotalus durissus

The morphologically undivided ventricle of the heart in non-crocodilian reptiles permits the mixing of oxygen-rich blood returning from the lungs and oxygen-poor blood from the systemic circulation. A possible functional significance for this intra-cardiac shunt has been debated for almost a century. Unilateral left vagotomy rendered the single effective pulmonary artery of the South American rattlesnake, Crotalus durissus, unable to adjust the magnitude of blood flow to the lung. The higher constant perfusion of the lung circulation and the incapability of adjusting the right-left shunt in left-denervated snakes persisted over time, providing a unique model for investigation of the long-term consequences of cardiac shunting in a squamate. Oxygen uptake recorded at rest and during spontaneous and forced activity was not affected by removing control of the cardiac shunt. Furthermore, metabolic rate and energetic balance during the post-prandial metabolic increment, plus the food conversion efficiency and growth rate, were all similarly unaffected. These results show that control of cardiac shunting is not associated with a clear functional advantage in adjusting metabolic rate, effectiveness of digestion or growth rates. © 2013. Published by The Company of Biologists Ltd.

Anaerobic running capacity determined from the critical velocity model is not significantly associated with maximal accumulated oxygen deficit in army runners

Purpose: The aim of this study was to verify whether there is an association between anaerobic running capacity (ARC) values, estimated from two-parameter models, and maximal accumulated oxygen deficit (MAOD) in army runners. Methods: Eleven, trained, middle distance runners who are members of the armed forces were recruited for the study (20 ± 1 years). They performed a critical velocity test (CV) for ARC estimation using three mathematical models and an MAOD test, both tests were applied on a motorized treadmill. Results: The MAOD was 61.6 ± 5.2 mL/kg (4.1 ± 0.3 L). The ARC values were 240.4 ± 18.6 m from the linear velocity-inverse time model, 254.0 ± 13.0 m from the linear distance-time model, and 275.2 ± 9.1 m from the hyperbolic time-velocity relationship (nonlinear 2-parameter model), whereas critical velocity values were 3.91 ± 0.07 m/s, 3.86 ± 0.08 m/s and 3.80 ± 0.09 m/s, respectively. There were differences (P < 0.05) for both the ARC and the CV values when compared between velocity-inverse time linear and nonlinear 2-parameter mathematical models. The different values of ARC did not significantly correlate with MAOD. Conclusion: In conclusion, estimated ARC did not correlate with MAOD, and should not be considered as an anaerobic measure of capacity for treadmill running. © 2013 Elsevier Masson SAS. All rights reserved.

Major components of energy drinks (caffeine, taurine, and guarana) exert cytotoxic effects on human neuronal SH-SY5Y cells by decreasing reactive oxygen species production

Scope. To elucidate the morphological and biochemical in vitro effects exerted by caffeine, taurine, and guarana, alone or in combination, since they are major components in energy drinks (EDs). Methods and Results. On human neuronal SH-SY5Y cells, caffeine (0.125-2 mg/mL), taurine (1-16 mg/mL), and guarana (3.125-50 mg/mL) showed concentration-dependent nonenzymatic antioxidant potential, decreased the basal levels of free radical generation, and reduced both superoxide dismutase (SOD) and catalase (CAT) activities, especially when combined together. However, guarana-treated cells developed signs of neurite degeneration in the form of swellings at various segments in a beaded or pearl chain-like appearance and fragmentation of such neurites at concentrations ranging from 12.5 to 50 mg/mL. Swellings, but not neuritic fragmentation, were detected when cells were treated with 0.5 mg/mL (or higher doses) of caffeine, concentrations that are present in EDs. Cells treated with guarana also showed qualitative signs of apoptosis, including membrane blebbing, cell shrinkage, and cleaved caspase-3 positivity. Flow cytometric analysis confirmed that cells treated with 12.5-50 mg/mL of guarana and its combinations with caffeine and/or taurine underwent apoptosis. Conclusion. Excessive removal of intracellular reactive oxygen species, to nonphysiological levels (or antioxidative stress), could be a cause of in vitro toxicity induced by these drugs. © 2013 Fares Zeidán-Chuliá et al.

Ferroelectric and structural instability of (Pb,Ca)TiO3 thin films prepared in an oxygen atmosphere and deposited on LSCO thin films which act as a buffer layer

Structural, microstructural and ferroelectric properties of Pb0.90Ca0.10TiO3 (PCT10) thin films deposited using La0.50Sr0.50CoO3 (LSCO) thin films which serve only as a buffer layer were compared with properties of the thin films grown using a platinum-coated silicon substrate. LSCO and PCT10 thin films were grown using the chemical solution deposition method and heat-treated in an oxygen atmosphere at 700 °C and 650 °C in a tube oven, respectively. X-ray diffraction (XRD) and Raman spectroscopy results showed that PCT10 thin films deposited directly on a platinum-coated silicon substrate exhibit a strong tetragonal character while thin films with the LSCO buffer layer displayed a smaller tetragonal character. Surface morphology observations by atomic force microscopy (AFM) revealed that PCT10 thin films with a LSCO buffer layer had a smoother surface and smaller grain size compared with thin films grown on a platinum-coated silicon substrate. Additionally, the capacitance versus voltage curves and hysteresis loop measurement indicated that the degree of polarization decreased for PCT10 thin films on a LSCO buffer layer compared with PCT10 thin films deposited directly on a platinum-coated silicon substrate. This phenomenon can be described as the smaller shift off-center of Ti atoms along the c-direction 〈001〉 inside the TiO6 octahedron unit due to the reduction of lattice parameters. Remnant polarization (P r ) values are about 30 μC/cm2 and 12 μC/cm2 for PCT10/Pt and PCT10/LSCO thin films, respectively. Results showed that the LSCO buffer layer strongly influenced the structural, microstructural and ferroelectric properties of PCT10 thin films. © 2013 Elsevier Ltd and Techna Group S.r.l.

Storage of sugarcane stalks (Saccharum officinarum cv. SP 79-1011) in low oxygen atmospheres and the effects on enzymatic browning

Although sugarcane consumption is very popular worldwide there are few studies regarding the postharvest storage of stalks that focus on controlling enzymatic browning. The objective of this study was to evaluate the quality of sugarcane stalks stored at 10±1°C in controlled atmosphere with various oxygen (O2) levels (1kPa, 5kPa, 10kPa, 15kPa, and 21kPa) and to verify the effect of this storage on the activities of polyphenoloxidase (PPO) and peroxidase (POD). At 1kPa and 5kPa O2, the stalks' respiratory rate, POD activity, and reducing sugar content were significantly less (P<0.05) than at higher O2 concentrations. In contrast, low O2 levels did not affect PPO activity or influence cane coloration. These results can be used to guide the choice of plastic films, making it possible to store sugarcane stalks in a controlled atmosphere. © 2013 Elsevier B.V.

Interstitial oxygen's influence on the corrosion behavior of Ti-9Mo alloys

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The Positive Effects of Priming Exercise on Oxygen Uptake Kinetics and High-Intensity Exercise Performance Are Not Magnified by a Fast-Start Pacing Strategy in Trained Cyclists

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

DFT Study on Ce-Doped Anatase TiO2: Nature of Ce3+ and Ti3+ Centers Triggered by Oxygen Vacancy Formation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of Oxygen Content and Microstructure on the Mechanical Properties and Biocompatibility of Ti-15 wt%Mo Alloy Used for Biomedical Applications

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The Influence of Small Quantities of Oxygen in the Structure, Microstructure, Hardness, Elasticity Modulus and Cytocompatibility of Ti-Zr Alloys for Dental Applications

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In Vitro Cytotoxicity of a Ti-35Nb-7Zr-5Ta Alloy Doped with Different Oxygen Contents

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The effects of different inspired oxygen fractions on gas exchange and Tei-index of myocardial performance in propofol-anesthetized dogs

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tailoring Thermal Transport Property of Graphene through Oxygen Functionalization

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)