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Sample records for acute oxygen sensing

  1. Ceramide Mediates Acute Oxygen Sensing in Vascular Tissues

    PubMed Central

    Moreno, Laura; Moral-Sanz, Javier; Morales-Cano, Daniel; Barreira, Bianca; Moreno, Enrique; Ferrarini, Alessia; Pandolfi, Rachele; Ruperez, Francisco J.; Cortijo, Julio; Sanchez-Luna, Manuel; Villamor, Eduardo; Perez-Vizcaino, Francisco

    2014-01-01

    Abstract Aims: A variety of vessels, such as resistance pulmonary arteries (PA) and fetoplacental arteries and the ductus arteriosus (DA) are specialized in sensing and responding to changes in oxygen tension. Despite opposite stimuli, normoxic DA contraction and hypoxic fetoplacental and PA vasoconstriction share some mechanistic features. Activation of neutral sphingomyelinase (nSMase) and subsequent ceramide production has been involved in hypoxic pulmonary vasoconstriction (HPV). Herein we aimed to study the possible role of nSMase-derived ceramide as a common factor in the acute oxygen-sensing function of specialized vascular tissues. Results: The nSMase inhibitor GW4869 and an anticeramide antibody reduced the hypoxic vasoconstriction in chicken PA and chorioallantoic arteries (CA) and the normoxic contraction of chicken DA. Incubation with interference RNA targeted to SMPD3 also inhibited HPV. Moreover, ceramide and reactive oxygen species production were increased by hypoxia in PA and by normoxia in DA. Either bacterial sphingomyelinase or ceramide mimicked the contractile responses of hypoxia in PA and CA and those of normoxia in the DA. Furthermore, ceramide inhibited voltage-gated potassium currents present in smooth muscle cells from PA and DA. Finally, the role of nSMase in acute oxygen sensing was also observed in human PA and DA. Innovation: These data provide evidence for the proposal that nSMase-derived ceramide is a critical player in acute oxygen-sensing in specialized vascular tissues. Conclusion: Our results indicate that an increase in ceramide generation is involved in the vasoconstrictor responses induced by two opposite stimuli, such as hypoxia (in PA and CA) and normoxia (in DA). Antioxid. Redox Signal. 20, 1–14. PMID:23725018

  2. Oxygen Sensing and Homeostasis

    PubMed Central

    Semenza, Gregg L.

    2015-01-01

    The discovery of carotid bodies as sensory receptors for detecting arterial blood oxygen levels, and the identification and elucidation of the roles of hypoxia-inducible factors (HIFs) in oxygen homeostasis have propelled the field of oxygen biology. This review highlights the gas-messenger signaling mechanisms associated with oxygen sensing, as well as transcriptional and non-transcriptional mechanisms underlying the maintenance of oxygen homeostasis by HIFs and their relevance to physiology and pathology. PMID:26328879

  3. Oxygen sensing and signaling.

    PubMed

    van Dongen, Joost T; Licausi, Francesco

    2015-01-01

    Oxygen is an indispensable substrate for many biochemical reactions in plants, including energy metabolism (respiration). Despite its importance, plants lack an active transport mechanism to distribute oxygen to all cells. Therefore, steep oxygen gradients occur within most plant tissues, which can be exacerbated by environmental perturbations that further reduce oxygen availability. Plants possess various responses to cope with spatial and temporal variations in oxygen availability, many of which involve metabolic adaptations to deal with energy crises induced by low oxygen. Responses are induced gradually when oxygen concentrations decrease and are rapidly reversed upon reoxygenation. A direct effect of the oxygen level can be observed in the stability, and thus activity, of various transcription factors that control the expression of hypoxia-induced genes. Additional signaling pathways are activated by the impact of oxygen deficiency on mitochondrial and chloroplast functioning. Here, we describe the molecular components of the oxygen-sensing pathway.

  4. L-type calcium channel: Clarifying the "oxygen sensing hypothesis".

    PubMed

    Cserne Szappanos, Henrietta; Viola, Helena; Hool, Livia C

    2017-03-18

    The heart is able to respond acutely to changes in oxygen tension. Since ion channels can respond rapidly to stimuli, the "ion channel oxygen sensing hypothesis" has been proposed to explain acute adaptation of cells to changes in oxygen demand. However the exact mechanism for oxygen sensing continues to be debated. Mitochondria consume the lion's share of oxygen in the heart, fuelling the production of ATP that drives excitation and contraction. Mitochondria also produce reactive oxygen species that are capable of altering the redox state of proteins. The cardiac L-type calcium channel is responsible for maintaining excitation and contraction. Recently, the reactive cysteine on the cardiac L-type calcium channel was identified. These data clarified that the channel does not respond directly to changes in oxygen tension, but rather responds to cellular redox state. This leads to acute alterations in cell signalling responsible for the development of arrhythmias and pathology.

  5. Oxygen and carbon dioxide sensing

    NASA Technical Reports Server (NTRS)

    Ren, Fan (Inventor); Pearton, Stephen John (Inventor)

    2012-01-01

    A high electron mobility transistor (HEMT) capable of performing as a CO.sub.2 or O.sub.2 sensor is disclosed, hi one implementation, a polymer solar cell can be connected to the HEMT for use in an infrared detection system. In a second implementation, a selective recognition layer can be provided on a gate region of the HEMT. For carbon dioxide sensing, the selective recognition layer can be, in one example, PEI/starch. For oxygen sensing, the selective recognition layer can be, in one example, indium zinc oxide (IZO). In one application, the HEMTs can be used for the detection of carbon dioxide and oxygen in exhaled breath or blood.

  6. Evolution and physiology of neural oxygen sensing

    PubMed Central

    Costa, Kauê M.; Accorsi-Mendonça, Daniela; Moraes, Davi J. A.; Machado, Benedito H.

    2014-01-01

    Major evolutionary trends in animal physiology have been heavily influenced by atmospheric O2 levels. Amongst other important factors, the increase in atmospheric O2 which occurred in the Pre-Cambrian and the development of aerobic respiration beckoned the evolution of animal organ systems that were dedicated to the absorption and transportation of O2, e.g., the respiratory and cardiovascular systems of vertebrates. Global variations of O2 levels in post-Cambrian periods have also been correlated with evolutionary changes in animal physiology, especially cardiorespiratory function. Oxygen transportation systems are, in our view, ultimately controlled by the brain related mechanisms, which senses changes in O2 availability and regulates autonomic and respiratory responses that ensure the survival of the organism in the face of hypoxic challenges. In vertebrates, the major sensorial system for oxygen sensing and responding to hypoxia is the peripheral chemoreflex neuronal pathways, which includes the oxygen chemosensitive glomus cells and several brainstem regions involved in the autonomic regulation of the cardiovascular system and respiratory control. In this review we discuss the concept that regulating O2 homeostasis was one of the primordial roles of the nervous system. We also review the physiology of the peripheral chemoreflex, focusing on the integrative repercussions of chemoreflex activation and the evolutionary importance of this system, which is essential for the survival of complex organisms such as vertebrates. The contribution of hypoxia and peripheral chemoreflex for the development of diseases associated to the cardiovascular and respiratory systems is also discussed in an evolutionary context. PMID:25161625

  7. Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads.

    PubMed

    Wang, Lin; Acosta, Miguel A; Leach, Jennie B; Carrier, Rebecca L

    2013-04-21

    Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of micro-environment oxygen level in 3D microfabricated cell culture systems.

  8. Nano-Enriched and Autonomous Sensing Framework for Dissolved Oxygen

    PubMed Central

    Shehata, Nader; Azab, Mohammed; Kandas, Ishac; Meehan, Kathleen

    2015-01-01

    This paper investigates a nano-enhanced wireless sensing framework for dissolved oxygen (DO). The system integrates a nanosensor that employs cerium oxide (ceria) nanoparticles to monitor the concentration of DO in aqueous media via optical fluorescence quenching. We propose a comprehensive sensing framework with the nanosensor equipped with a digital interface where the sensor output is digitized and dispatched wirelessly to a trustworthy data collection and analysis framework for consolidation and information extraction. The proposed system collects and processes the sensor readings to provide clear indications about the current or the anticipated dissolved oxygen levels in the aqueous media. PMID:26287211

  9. Nano-Enriched and Autonomous Sensing Framework for Dissolved Oxygen.

    PubMed

    Shehata, Nader; Azab, Mohammed; Kandas, Ishac; Meehan, Kathleen

    2015-08-14

    This paper investigates a nano-enhanced wireless sensing framework for dissolved oxygen (DO). The system integrates a nanosensor that employs cerium oxide (ceria) nanoparticles to monitor the concentration of DO in aqueous media via optical fluorescence quenching. We propose a comprehensive sensing framework with the nanosensor equipped with a digital interface where the sensor output is digitized and dispatched wirelessly to a trustworthy data collection and analysis framework for consolidation and information extraction. The proposed system collects and processes the sensor readings to provide clear indications about the current or the anticipated dissolved oxygen levels in the aqueous media.

  10. Hydrogen sulfide and oxygen sensing in the cardiovascular system.

    PubMed

    Olson, Kenneth R; Whitfield, Nathan L

    2010-05-15

    Vertebrate cardiorespiratory homeostasis is inextricably dependent upon specialized cells that provide feedback on oxygen status in the tissues, blood, and on occasion, environment. These "oxygen sensing" cells include chemoreceptors and oxygen-sensitive chromaffin cells that initiate cardiorespiratory reflexes, vascular smooth muscle cells that adjust perfusion to metabolism or ventilation, and other cells that condition themselves in response to episodic hypoxia. Identification of how these cells sense oxygen and transduce this into the appropriate physiological response has enormous clinical applicability, but despite intense research there is no consensus regarding the initial hypoxia-effector coupling mechanism. This review examines an alternative mechanism of oxygen sensing using oxidation of endogenously produced hydrogen sulfide (H(2)S) as the O(2)-sensitive couple. Support for this hypothesis includes the similarity of effects of hypoxia and H(2)S on a variety of tissues, augmentation of hypoxic responses by precursors of H(2)S production and their inhibition by inhibitors of H(2)S synthesis, and the rapid consumption of H(2)S by O(2) in the range of intracellular/mitochondrial Po(2). These studies also indicate that, under normoxic conditions, it is doubtful that free H(2)S has longer than a transient existence in tissue or extracellular fluid.

  11. Oxygen sensing characteristics of individual ZnO nanowire transistors

    SciTech Connect

    Li, Q.H.; Liang, Y.X.; Wan, Q.; Wang, T.H.

    2004-12-27

    Individual ZnO nanowire transistors are fabricated, and their sensing properties are investigated. The transistors show a carrier density of 2300 {mu}m{sup -1} and mobility up to 6.4 cm{sup 2}/V s, which are obtained from the I{sub SD}-V{sub G} curves. The threshold voltage shifts in the positive direction and the source-drain current decreases as ambient oxygen concentration increases. However, the opposite occurs when the transistors are under illumination. Surface adsorbates on the ZnO nanowires affect both the mobility and the carrier density. Our data are helpful in understanding the sensing mechanism of the gas sensors.

  12. Quality assessment of packaged foods by optical oxygen sensing

    NASA Astrophysics Data System (ADS)

    Papkovsky, Dmitri B.; O'Mahony, Fiach C.; Kerry, Joe P.; Ogurtsov, Vladimir I.

    2005-11-01

    A phase-fluorometric oxygen sensor system has been developed, which allows non-destructive measurement of residual oxygen levels in sealed containers such as packaged foods. It operates with disposable solid-state sensors incorporated in each pack, and a portable detector which interrogates with the sensors through a (semi)transparent packaging material. The system has been optimized for packaging applications and validated in small and medium scale trials with different types of food, including MAP hams, cheese, convenience foods, smoked fish, bakery. It has demonstrated high efficiency in monitoring package integrity, oxygen profiles in packs, performance of packaging process and many other research and quality control tasks, allowing control of 100% of packs. The low-cost batch-calibrated sensors have demonstrated reliability, safety, stability including direct contact with food, high efficiency in the low oxygen range. Another system, which also employs the fluorescence-based oxygen sensing approach, provides rapid assessment of microbial contamination (total viable counts) in complex samples such as food homogenates, industrial waste, environmental samples, etc. It uses soluble oxygen-sensitive probes, standard microtitter plates and fluorescence measurements on conventional plate reader to monitor growth of aerobic bacteria in small test samples (e.g. food homogenates) via their oxygen respiration. The assay provides high sample through put, miniaturization, speed, and can serve as alternative to the established methods such as agar plate colony counts and turbidimetry.

  13. High flow nasal oxygen in acute respiratory failure.

    PubMed

    Ricard, J-D

    2012-07-01

    Use of high flow nasal cannula oxygen (HFNC) is increasingly popular in adult ICUs for patients with acute hypoxemic respiratory failure. This is the result of the successful long-term use of HFNC in the neonatal field and recent clinical data in adults indicating beneficial effects of HFNC over conventional facemask oxygen therapy. HFNC rapidly alleviates symptoms of respiratory distress and improves oxygenation by several mechanisms, including deadspace washout, reduction in oxygen dilution and in inspiratory nasopharyngeal resistance, a moderate positive airway pressure effect that may generate alveolar recruitment and an overall greater tolerance and comfort with the interface and the heated and humidified inspired gases. Indications of HFNC are broad, encompassing most if not all causes of acute hypoxemic respiratory failure. HFNC can also provide oxygen during invasive procedures, and be used to prevent or treat post-extubation respiratory failure. HFNC may also alleviate respiratory distress in patients at a palliative stage. Although observational studies suggest that HFNC might reduce the need for intubation in acute hypoxemic respiratory failure; such a reduction has not yet been demonstrated. Beyond this potential additional effect on outcome, the evidence already published argues in favor of the large use of HFNC as first line therapy for acute respiratory failure.

  14. Vitamin C is dispensable for oxygen sensing in vivo

    PubMed Central

    Nytko, Katarzyna J.; Maeda, Nobuyo; Schläfli, Philipp; Spielmann, Patrick; Wenger, Roland H.

    2011-01-01

    Prolyl-4-hydroxylation is necessary for proper structural assembly of collagens and oxygen-dependent protein stability of hypoxia-inducible transcription factors (HIFs). In vitro function of HIF prolyl-4-hydroxylase domain (PHD) enzymes requires oxygen and 2-oxoglutarate as cosubstrates with iron(II) and vitamin C serving as cofactors. Although vitamin C deficiency is known to cause the collagen-disassembly disease scurvy, it is unclear whether cellular oxygen sensing is similarly affected. Here, we report that vitamin C–deprived Gulo−/− knockout mice show normal HIF-dependent gene expression. The systemic response of Gulo−/− animals to inspiratory hypoxia, as measured by plasma erythropoietin levels, was similar to that of animals supplemented with vitamin C. Hypoxic HIF induction was also essentially normal under serum- and vitamin C–free cell-culture conditions, suggesting that vitamin C is not required for oxygen sensing in vivo. Glutathione was found to fully substitute for vitamin C requirement of all 3 PHD isoforms in vitro. Consistently, glutathione also reduced HIF-1α protein levels, transactivation activity, and endogenous target gene expression in cells exposed to CoCl2. A Cys201Ser mutation in PHD2 increased basal hydroxylation rates and conferred resistance to oxidative damage in vitro, suggesting that this surface-accessible PHD2 cysteine residue is a target of antioxidative protection by vitamin C and glutathione. PMID:21346252

  15. Extracorporeal membrane oxygenation in adults for severe acute respiratory failure.

    PubMed

    Rozé, H; Repusseau, B; Ouattara, A

    2014-01-01

    The purpose of this review is to examine the indications of extracorporeal membrane oxygenation (ECMO) for severe acute respiratory distress syndrome (ARDS). This technique of oxygenation has significantly increased worldwide with the H1N1 flu pandemic. The goal of ECMO is to maintain a safe level of oxygenation and controlled respiratory acidosis under protective ventilation. The enthusiasm for ECMO should not obscure the consideration for potential associated complications. Before widespread diffusion of ECMO, new trials should test the efficacy of early initiation or CO2 removal in addition to, or even as an alternative to mechanical ventilation for severe ARDS.

  16. Normobaric oxygen treatment in acute ischemic stroke: a clinical perspective

    PubMed Central

    Shi, Shu-hai; Qi, Zhi-feng; Luo, Yu-min; Ji, Xun-ming; Liu, Ke Jian

    2016-01-01

    Acute ischemic stroke is a common and serious neurological disease. Oxygen therapy has been shown to increase oxygen supply to ischemic tissues and improve outcomes after cerebral ischemia/reperfusion. Normobaric hyperoxia (NBO), an easily applicable and non-invasive method, shows protective effects on acute ischemic stroke animals and patients in pilot studies. However, many critical scientific questions are still unclear, such as the therapeutic time window of NBO, the long-term effects and the benefits of NBO in large clinic trials. In this article, we review the current literatures on NBO treatment of acute ischemic stroke in preclinical and clinical studies and try to analyze and identify the key gaps or unknowns in our understanding about NBO. Based on these analyses, we provide suggestions for future studies. PMID:27867482

  17. Oxygen Sensing by Arterial Chemoreceptors Depends on Mitochondrial Complex I Signaling.

    PubMed

    Fernández-Agüera, M Carmen; Gao, Lin; González-Rodríguez, Patricia; Pintado, C Oscar; Arias-Mayenco, Ignacio; García-Flores, Paula; García-Pergañeda, Antonio; Pascual, Alberto; Ortega-Sáenz, Patricia; López-Barneo, José

    2015-11-03

    O2 sensing is essential for mammalian homeostasis. Peripheral chemoreceptors such as the carotid body (CB) contain cells with O2-sensitive K(+) channels, which are inhibited by hypoxia to trigger fast adaptive cardiorespiratory reflexes. How variations of O2 tension (PO2) are detected and the mechanisms whereby these changes are conveyed to membrane ion channels have remained elusive. We have studied acute O2 sensing in conditional knockout mice lacking mitochondrial complex I (MCI) genes. We inactivated Ndufs2, which encodes a protein that participates in ubiquinone binding. Ndufs2-null mice lose the hyperventilatory response to hypoxia, although they respond to hypercapnia. Ndufs2-deficient CB cells have normal functions and ATP content but are insensitive to changes in PO2. Our data suggest that chemoreceptor cells have a specialized succinate-dependent metabolism that induces an MCI state during hypoxia, characterized by the production of reactive oxygen species and accumulation of reduced pyridine nucleotides, which signal neighboring K(+) channels.

  18. Interaction of Hydrogen Sulfide with Oxygen Sensing under Hypoxia

    PubMed Central

    Wu, Bo; Teng, Huajian; Zhang, Li; Li, Hong; Li, Jing; Wang, Lina; Li, Hongzhu

    2015-01-01

    Based on the discovery of endogenous H2S production, many in depth studies show this gasotransmitter with a variety of physiological and pathological functions. Three enzymes, cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (MST), are involved in enzymatic production of H2S. Emerging evidence has elucidated an important protective role of H2S in hypoxic conditions in many mammalian systems. However, the mechanisms by which H2S senses and responses to hypoxia are largely elusive. Hypoxia-inducible factors (HIFs) function as key regulators of oxygen sensing, activating target genes expression under hypoxia. Recent studies have shown that exogenous H2S regulates HIF action in different patterns. The activation of carotid bodies is a sensitive and prompt response to hypoxia, rapidly enhancing general O2 supply. H2S has been identified as an excitatory mediator of hypoxic sensing in the carotid bodies. This paper presents a brief review of the roles of these two pathways which contribute to hypoxic sensing of H2S. PMID:26078818

  19. Acute pulmonary edema secondary to hyperbaric oxygen therapy

    PubMed Central

    Obiagwu, Chukwudi; Paul, Vishesh; Chadha, Sameer; Hollander, Gerald; Shani, Jacob

    2015-01-01

    Hyperbaric oxygen therapy (HBOT) has been shown to be effective in the treatment of diabetic ulcers, air embolism, carbon monoxide poisoning and gas gangrene with minimal adverse effects. Very few cases of HBOT causing acute pulmonary edema (PE) has been described; with a study on dogs suggesting that a complication of this therapy could be PE. We describe the case of an 80-year-old man with a history of stable systolic heart failure and diabetes mellitus presenting with acute PE following treatment with HBOT for diabetic foot. PMID:25988073

  20. Acute oxygen therapy: a review of prescribing and delivery practices

    PubMed Central

    Cousins, Joyce L; Wark, Peter AB; McDonald, Vanessa M

    2016-01-01

    Oxygen is a commonly used drug in the clinical setting and like other drugs its use must be considered carefully. This is particularly true for those patients who are at risk of type II respiratory failure in whom the risk of hypercapnia is well established. In recent times, several international bodies have advocated for the prescription of oxygen therapy in an attempt to reduce this risk in vulnerable patient groups. Despite this guidance, published data have demonstrated that there has been poor uptake of these recommendations. Multiple interventions have been tested to improve concordance, and while some of these interventions show promise, the sustainability of these interventions are less convincing. In this review, we summarize data that have been published on the prevalence of oxygen prescription and the accurate and appropriate administration of this drug therapy. We also identify strategies that have shown promise in facilitating changes to oxygen prescription and delivery practice. There is a clear need to investigate the barriers, facilitators, and attitudes of clinicians in relation to the prescription of oxygen therapy in acute care. Interventions based on these findings then need to be designed and tested to facilitate the application of evidence-based guidelines to support sustained changes in practice, and ultimately improve patient care. PMID:27307722

  1. Neurohistological Investigations on General Oxygen Deficiency of the Brain. 2. The Behavior of Astocytes After Acute and Subacute Death

    DTIC Science & Technology

    1951-03-01

    clasmatodendrosis might be explained as a con- deprived of the oxygen supply, causing the acute sequence of a necrobiosis caused by the arrest onset...odendrosis is a necrobiosis His opinion brief instant anoxia has not a deadly hut a stimo- rust now be modified to allow for the fact that ulative effect...in a strict sense does not exist. It is actually a necrobiosis of Astrocytes within a tissue infiltrate in a case of an the cells, which is

  2. Effects of normobaric versus hyperbaric oxygen on cell injury induced by oxygen and glucose deprivation in acute brain slices

    PubMed Central

    Chazalviel, Laurent; Blatteau, Jean-Eric; Vallée, Nicolas; Risso, Jean-Jacques; Besnard, Stéphane; Abraini, Jacques H.

    2016-01-01

    Normobaric oxygen (NBO) and hyperbaric oxygen (HBO) are emerging as a possible co-treatment of acute ischemic stroke. Both have been shown to reduce infarct volume, to improve neurologic outcome, to promote endogenous tissue plasminogen activator-induced thrombolysis and cerebral blood flow, and to improve tissue oxygenation through oxygen diffusion in the ischemic areas, thereby questioning the interest of HBO compared to NBO. In the present study, in order to investigate and compare the oxygen diffusion effects of NBO and HBO on acute ischemic stroke independently of their effects at the vascular level, we used acute brain slices exposed to oxygen and glucose deprivation, an ex vivo model of brain ischemia that allows investigating the acute effects of NBO (partial pressure of oxygen (pO2) = 1 atmospheres absolute (ATA) = 0.1 MPa) and HBO (pO2 = 2.5 ATA = 0.25 MPa) through tissue oxygenation on ischemia-induced cell injury as measured by the release of lactate dehydrogenase. We found that HBO, but not NBO, reduced oxygen and glucose deprivation-induced cell injury, indicating that passive tissue oxygenation (i.e. without vascular support) of the brain parenchyma requires oxygen partial pressure higher than 1 ATA. PMID:27867486

  3. Effects of normobaric versus hyperbaric oxygen on cell injury induced by oxygen and glucose deprivation in acute brain slices.

    PubMed

    Chazalviel, Laurent; Blatteau, Jean-Eric; Vallée, Nicolas; Risso, Jean-Jacques; Besnard, Stéphane; Abraini, Jacques H

    2016-01-01

    Normobaric oxygen (NBO) and hyperbaric oxygen (HBO) are emerging as a possible co-treatment of acute ischemic stroke. Both have been shown to reduce infarct volume, to improve neurologic outcome, to promote endogenous tissue plasminogen activator-induced thrombolysis and cerebral blood flow, and to improve tissue oxygenation through oxygen diffusion in the ischemic areas, thereby questioning the interest of HBO compared to NBO. In the present study, in order to investigate and compare the oxygen diffusion effects of NBO and HBO on acute ischemic stroke independently of their effects at the vascular level, we used acute brain slices exposed to oxygen and glucose deprivation, an ex vivo model of brain ischemia that allows investigating the acute effects of NBO (partial pressure of oxygen (pO2) = 1 atmospheres absolute (ATA) = 0.1 MPa) and HBO (pO2 = 2.5 ATA = 0.25 MPa) through tissue oxygenation on ischemia-induced cell injury as measured by the release of lactate dehydrogenase. We found that HBO, but not NBO, reduced oxygen and glucose deprivation-induced cell injury, indicating that passive tissue oxygenation (i.e. without vascular support) of the brain parenchyma requires oxygen partial pressure higher than 1 ATA.

  4. Oxygen-sensing by arterial chemoreceptors: Mechanisms and medical translation.

    PubMed

    López-Barneo, José; Ortega-Sáenz, Patricia; González-Rodríguez, Patricia; Fernández-Agüera, M Carmen; Macías, David; Pardal, Ricardo; Gao, Lin

    2016-01-01

    Acute O2 sensing is necessary for the activation of cardiorespiratory reflexes (hyperventilation and sympathetic activation), which permit the survival of individuals under hypoxic environments (e.g. high altitude) or medical conditions presenting with reduced capacity for gas exchange between the lung alveoli and the blood. Changes in blood O2 tension are detected by the arterial chemoreceptors, in particular the carotid body (CB), which act in concert with the adrenal medulla (AM) to facilitate rapid adaptations to hypoxia. The field of arterial chemoreception has undergone a considerable expansion in recent years, with many of the fundamental observations made at the molecular and cellular levels serving to improve our understanding of the pathogenesis of numerous medical disorders, and even to propose advances in the treatment strategies. In this review, after a short historical preface, we describe the current model of chemosensory transduction based on the modulation of membrane K(+) channels by O2 in specialized chemoreceptor cells. Recent progress in elucidating the molecular mechanisms underlying the modulation of ion channels by O2 tension, which involves mitochondrial complex I, is also discussed. The discovery in the last few years of a specific population of neural crest-derived stem cells in the CB explains the reversible growth of this organ, an intriguing and unusual property of this type of neuronal tissue that contributes to acclimatization under chronic hypoxia. The essential homeostatic role of the CB-AM axis is clearly evident in newly generated mouse models that reach adulthood, albeit with CB and AM atrophy. These animals exhibit a marked intolerance to even mild hypoxia. CB inhibition or over-activation can have important medical consequences. Respiratory depression by general anesthetics or by opioid use is a common clinical condition that frequently causes death in susceptible individuals. An exaggerated sympathetic outflow due to over

  5. Reactive oxygen species in eradicating acute myeloid leukemic stem cells

    PubMed Central

    Zhang, Hui; Fang, Hai

    2014-01-01

    Leukemic stem cells (LSCs) have been proven to drive leukemia initiation, progression and relapse, and are increasingly being used as a critical target for therapeutic intervention. As an essential feature in LSCs, reactive oxygen species (ROS) homeostasis has been extensively exploited in the past decade for targeting LSCs in acute myeloid leukemia (AML). Most, if not all, agents that show therapeutic benefits are able to alter redox status by inducing ROS, which confers selectivity in eradicating AML stem cells but sparing normal counterparts. In this review, we provide the comprehensive update of ROS-generating agents in the context of their impacts on our understanding of the pathogenesis of AML and its therapy. We anticipate that further characterizing these ROS agents will help us combat against AML in the coming era of LSC-targeting strategy. PMID:27358859

  6. Oxygen sensing by the carotid body: mechanisms and role in adaptation to hypoxia.

    PubMed

    López-Barneo, José; González-Rodríguez, Patricia; Gao, Lin; Fernández-Agüera, M Carmen; Pardal, Ricardo; Ortega-Sáenz, Patricia

    2016-04-15

    Oxygen (O2) is fundamental for cell and whole-body homeostasis. Our understanding of the adaptive processes that take place in response to a lack of O2(hypoxia) has progressed significantly in recent years. The carotid body (CB) is the main arterial chemoreceptor that mediates the acute cardiorespiratory reflexes (hyperventilation and sympathetic activation) triggered by hypoxia. The CB is composed of clusters of cells (glomeruli) in close contact with blood vessels and nerve fibers. Glomus cells, the O2-sensitive elements in the CB, are neuron-like cells that contain O2-sensitive K(+)channels, which are inhibited by hypoxia. This leads to cell depolarization, Ca(2+)entry, and the release of transmitters to activate sensory fibers terminating at the respiratory center. The mechanism whereby O2modulates K(+)channels has remained elusive, although several appealing hypotheses have been postulated. Recent data suggest that mitochondria complex I signaling to membrane K(+)channels plays a fundamental role in acute O2sensing. CB activation during exposure to low Po2is also necessary for acclimatization to chronic hypoxia. CB growth during sustained hypoxia depends on the activation of a resident population of stem cells, which are also activated by transmitters released from the O2-sensitive glomus cells. These advances should foster further studies on the role of CB dysfunction in the pathogenesis of highly prevalent human diseases.

  7. Renal oxygenation in acute renal ischemia-reperfusion injury.

    PubMed

    Abdelkader, Amany; Ho, Julie; Ow, Connie P C; Eppel, Gabriela A; Rajapakse, Niwanthi W; Schlaich, Markus P; Evans, Roger G

    2014-05-01

    Tissue hypoxia has been demonstrated, in both the renal cortex and medulla, during the acute phase of reperfusion after ischemia induced by occlusion of the aorta upstream from the kidney. However, there are also recent clinical observations indicating relatively well preserved oxygenation in the nonfunctional transplanted kidney. To test whether severe acute kidney injury can occur in the absence of widespread renal tissue hypoxia, we measured cortical and inner medullary tissue Po2 as well as total renal O2 delivery (Do2) and O2 consumption (Vo2) during the first 2 h of reperfusion after 60 min of occlusion of the renal artery in anesthetized rats. To perform this experiment, we used a new method for measuring kidney Do2 and Vo2 that relies on implantation of fluorescence optodes in the femoral artery and renal vein. We were unable to detect reductions in renal cortical or inner medullary tissue Po2 during reperfusion after ischemia localized to the kidney. This is likely explained by the observation that Vo2 (-57%) was reduced by at least as much as Do2 (-45%), due to a large reduction in glomerular filtration (-94%). However, localized tissue hypoxia, as evidence by pimonidazole adduct immunohistochemistry, was detected in kidneys subjected to ischemia and reperfusion, particularly in, but not exclusive to, the outer medulla. Thus, cellular hypoxia, particularly in the outer medulla, may still be present during reperfusion even when reductions in tissue Po2 are not detected in the cortex or inner medulla.

  8. Lifetime-based photoacoustic oxygen sensing in vivo

    NASA Astrophysics Data System (ADS)

    Ray, Aniruddha; Rajian, Justin Rajesh; Lee, Yong-Eun Koo; Wang, Xueding; Kopelman, Raoul

    2012-05-01

    The determination of oxygen levels in blood and other tissues in vivo is critical for ensuring proper body functioning, for monitoring the status of many diseases, such as cancer, and for predicting the efficacy of therapy. Here we demonstrate, for the first time, a lifetime-based photoacoustic technique for the measurement of oxygen in vivo, using an oxygen sensitive dye, enabling real time quantification of blood oxygenation. The results from the main artery in the rat tail indicated that the lifetime of the dye, quantified by the photoacoustic technique, showed a linear relationship with the blood oxygenation levels in the targeted artery.

  9. Modulation of perfusion and oxygenation by red blood cell oxygen affinity during acute anemia.

    PubMed

    Cabrales, Pedro; Tsai, Amy G; Intaglietta, Marcos

    2008-03-01

    Responses to exchange transfusion using red blood cells (RBCs) with modified hemoglobin (Hb) oxygen (O(2)) affinity were studied in the hamster window chamber model during acute anemia to determine its role on microvascular perfusion and tissue oxygenation. Allosteric effectors were introduced in the RBCs by electroporation. Inositol hexaphosphate (IHP) and 5-hydroxymethyl-2-furfural (5HMF) were used to decrease and increase Hb-O(2) affinity. In vitro P50s (partial pressure of O(2) at 50% Hb saturation) were modified to 10, 25, 45, and 50 mm Hg (normal P50 is 32 mm Hg). Allosteric effectors also decreased the Hill coefficient. Anemic condition was induced by isovolemic hemodilution exchanges using 6% dextran 70 kD to 18% hematocrit (Hct). Modified RBCs (at 18% Hct in 5% albumin solution) were infused by exchange transfusion of 35% of blood volume. Systemic parameters, microvascular perfusion, capillary perfusion (functional capillary density, FCD), and microvascular Po(2) levels were measured. RBcs with P50 of 45 mm Hg increased tissue Po(2) and decreased O(2) delivery (Do(2)) and extraction (Vo(2)) and RBCs with P50 of 60 mmHg reduced FCD, microvascular flow, tissue Po(2), Do(2) and Vo(2). Erythrocytes with increased Hb-O(2) affinity maintained hemodynamic conditions, Do(2) and decreased tissue Po(2). This study shows that in an anemic condition, maximal tissue Po(2) does not correspond to maximal Do(2) and Vo(2).

  10. Multifunctional mesoporous nanocomposites with magnetic, optical, and sensing features: synthesis, characterization, and their oxygen-sensing performance.

    PubMed

    Wang, Yanyan; Li, Bin; Zhang, Liming; Song, Hang

    2013-01-29

    In this paper, the fabrication, characterization, and application in oxygen sensing are reported for a novel multifunctional nanomaterial of [Ru(bpy)(2)phen-MMS] (bpy, 2,2'-bipyridyl; phen, phenathrolin) which was simply prepared by covalently grafting the ruthenium(II) polypyridyl compounds into the channels of magnetic mesoporous silica nanocomposites (MMS). Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N(2) adsorption-desorption, a superconducting quantum interference device, UV-vis spectroscopy, and photoluminescence spectra were used to characterize the samples. The well-designed multifunctional nanocomposites show superparamagnetic behavior and ordered mesoporous characteristics and exhibit a strong red-orange metal-to-ligand charge transfer emission. In addition, the obtained nanocomposites give high performance in oxygen sensing with high sensitivity (I(0)/I(100) = 5.2), good Stern-Volmer characteristics (R(2) = 0.9995), and short response/recovery times (t↓ = 6 s and t↑ = 12 s). The magnetic, mesoporous, luminescent, and oxygen-sensing properties of this multifunctional nanostructure make it hold great promise as a novel multifunctional oxygen-sensing system for chemical/biosensor.

  11. Distributed fiber optical sensing of oxygen with optical time domain reflectometry.

    PubMed

    Eich, Susanne; Schmälzlin, Elmar; Löhmannsröben, Hans-Gerd

    2013-05-31

    In many biological and environmental applications spatially resolved sensing of molecular oxygen is desirable. A powerful tool for distributed measurements is optical time domain reflectometry (OTDR) which is often used in the field of telecommunications. We combine this technique with a novel optical oxygen sensor dye, triangular-[4] phenylene (TP), immobilized in a polymer matrix. The TP luminescence decay time is 86 ns. The short decay time of the sensor dye is suitable to achieve a spatial resolution of some meters. In this paper we present the development and characterization of a reflectometer in the UV range of the electromagnetic spectrum as well as optical oxygen sensing with different fiber arrangements.

  12. A Pyrene@Micelle Sensor for Fluorescent Oxygen Sensing

    PubMed Central

    Yuan, Yan-xia; Peng, Hong-shang; Ping, Jian-tao; Wang, Xiao-hui; You, Fang-tian

    2015-01-01

    For most fluorescent oxygen sensors developed today, their fabrication process is either time-consuming or needs specialized knowledge. In this work, a robust fluorescent oxygen sensor is facilely constructed by dissolving pyrene molecules into CTAB aqueous solution. The as-prepared pyrene@micelle sensors have submicron-sized diameter, and the concentration of utilized pyrene can be reduced as low as 0.8 mM but still can exhibit dominant excimer emission. The excimer fluorescence is sensitive to dissolved oxygen in both intensity and lifetime, and the respective Stern-Volmer plot follows a nonlinear behavior justified by a two-site model. Because of the merits of large Stokes shift (~140 nm), easy fabrication, and robustness, the pyrene@micelle sensors are very attractive for practical determination of oxygen. PMID:26539471

  13. A rhenium complex doped in a silica molecular sieve for molecular oxygen sensing: Construction and characterization

    NASA Astrophysics Data System (ADS)

    Yang, Xiaozhou; Li, Yanxiao

    2016-01-01

    This paper reported a diamine ligand and its Re(I) complex for potential application in oxygen sensing. The novelty of this diamine ligand localized at its increased conjugation chain which had a typical electron-withdrawing group of 1,3,4-oxadiazole. Electronic distribution of excited electrons and their lifetime were supposed to be increased, favoring oxygen sensing collision. This hypothesis was confirmed by single crystal analysis, theoretical calculation and photophysical measurement. It was found that this Re(I) complex had a long-lived emission peaking at 545 nm, favoring sensing application. By doping this complex into a silica matrix MCM-41, oxygen sensing performance and mechanism of the resulting composites were discussed in detail. Non-linear Stern-Volmer working curves were observed with maximum sensitivity of 5.54 and short response time of 6 s.

  14. Oxygen and life on earth: an anesthesiologist's views on oxygen evolution, discovery, sensing, and utilization.

    PubMed

    Lindahl, Sten G E

    2008-07-01

    The advent of oxygenic photosynthesis and the accumulation of oxygen in our atmosphere opened up new possibilities for the development of life on Earth. The availability of oxygen, the most capable electron acceptor on our planet, allowed the development of highly efficient energy production from oxidative phosphorylation, which shaped the evolutionary development of aerobic life forms from the first multicellular organisms to the vertebrates.

  15. Luminescent sensing and imaging of oxygen: Fierce competition to the Clark electrode

    PubMed Central

    2015-01-01

    Luminescence‐based sensing schemes for oxygen have experienced a fast growth and are in the process of replacing the Clark electrode in many fields. Unlike electrodes, sensing is not limited to point measurements via fiber optic microsensors, but includes additional features such as planar sensing, imaging, and intracellular assays using nanosized sensor particles. In this essay, I review and discuss the essentials of (i) common solid‐state sensor approaches based on the use of luminescent indicator dyes and host polymers; (ii) fiber optic and planar sensing schemes; (iii) nanoparticle‐based intracellular sensing; and (iv) common spectroscopies. Optical sensors are also capable of multiple simultaneous sensing (such as O2 and temperature). Sensors for O2 are produced nowadays in large quantities in industry. Fields of application include sensing of O2 in plant and animal physiology, in clinical chemistry, in marine sciences, in the chemical industry and in process biotechnology. PMID:26113255

  16. A microfluidic device for continuous sensing of systemic acute toxicants in drinking water.

    PubMed

    Zhao, Xinyan; Dong, Tao

    2013-12-03

    A bioluminescent-cell-based microfluidic device for sensing toxicants in drinking water was designed and fabricated. The system employed Vibrio fischeri cells as broad-spectrum sensors to monitor potential systemic cell toxicants in water, such as heavy metal ions and phenol. Specifically, the chip was designed for continuous detection. The chip design included two counter-flow micromixers, a T-junction droplet generator and six spiral microchannels. The cell suspension and water sample were introduced into the micromixers and dispersed into droplets in the air flow. This guaranteed sufficient oxygen supply for the cell sensors. Copper (Cu2+), zinc (Zn2+), potassium dichromate and 3,5-dichlorophenol were selected as typical toxicants to validate the sensing system. Preliminary tests verified that the system was an effective screening tool for acute toxicants although it could not recognize or quantify specific toxicants. A distinct non-linear relationship was observed between the zinc ion concentration and the Relative Luminescence Units (RLU) obtained during testing. Thus, the concentration of simple toxic chemicals in water can be roughly estimated by this system. The proposed device shows great promise for an early warning system for water safety.

  17. Percutaneous extracorporeal membrane oxygenation for cardiogenic shock due to acute fulminant myocarditis.

    PubMed

    Fayssoil, Abdallah; Nardi, Olivier; Orlikowski, David; Combes, Alain; Chastre, Jean; Annane, Djillali

    2010-02-01

    Percutaneous extracorporeal membrane oxygenation is an invasive technique that provides emergent circulatory support for patients with cardiogenic shock. We report a favorable outcome of an acute fulminant myocarditis in a 25-year-old myasthenia patient with cardiogenic shock supported by percutaneous extracorporeal membrane oxygenation.

  18. Eliminating the Interference of Oxygen for Sensing Hydrogen Peroxide with the Polyaniline Modified Electrode

    PubMed Central

    Gu, Yesong; Chen, Chien-Chung

    2008-01-01

    Polyaniline (PANI) has been shown to possess excellent catalytic activity toward oxygen reduction, however, this molecule may interfere with the electrochemical measurement of other targets when using a polyaniline modified platinum (PANI/Pt) electrode. In this study, we have demonstrated the considerable effects of dissolved oxygen on the sensing of hydrogen peroxide with the PANI/Pt electrode. Accordingly, we proposed a strategy to eliminate the influence of dissolved oxygen with oxygen scavengers. Our results indicated that as an oxygen scavenger sodium thiosulfate was very effective in the removal of dissolved oxygen from the sample solution, and had negligible effect on the quantification of hydrogen peroxide when its applied concentration was below 1 mM. PMID:27873985

  19. High performance oxygen sensing nanofibrous membranes of Eu(III) complex/polystyrene prepared by electrospinning

    NASA Astrophysics Data System (ADS)

    Yingkui, Li

    2011-07-01

    In this paper, we report the synthesis, characterization, crystal structure, and photophysical properties of a Eu 3+ complex of Eu(TTA) 3Phen, where TTA = 2-thenoyltrifluoroacetonate, and Phen = 1,10-phenanthroline. Its elementary application for oxygen-sensing application is also investigated by doping it into a polymer matrix of polystyrene (PS). Experimental data suggest that the 3 wt% doped Eu(TTA) 3Phen nanofibrous membrane exhibits a high sensitivity of 3.4 towards oxygen with a good linear relationship of R2 = 0.996. In addition, the 3 wt% doped Eu(TTA) 3Phen nanofibrous membrane owns a quick response of 9 s towards molecular oxygen, along with its excellent atmosphere insensitivity and photobleaching resistance. All these results suggest that both Eu(TTA) 3Phen and Eu(TTA) 3Phen/PS system are promising candidates for oxygen-sensing optical sensors.

  20. Extracorporeal membrane oxygenation as a rescue therapy for acute respiratory failure during chemotherapy in a patient with acute myeloid leukemia

    PubMed Central

    Lee, Sang Won; Kim, Youn Seup

    2017-01-01

    Acute respiratory distress syndrome (ARDS) caused by pneumonia in patients with hematologic malignancies can be life-threatening. Extracorporeal membrane oxygenation (ECMO) is the only temporary treatment for patients with ARDS who are refractory to conventional treatment. However, the immunosuppression and coagulopathies in hematological malignancies such as lymphoma and acute leukemia are relative contraindications for ECMO, due to high risks of infection and bleeding. Here, we report a 22-year-old man with acute myeloid leukemia (AML) who developed pneumonia and ARDS during induction chemotherapy; he was treated with ECMO. PMID:28275497

  1. Extracorporeal membrane oxygenation as a rescue therapy for acute respiratory failure during chemotherapy in a patient with acute myeloid leukemia.

    PubMed

    Lee, Sang Won; Kim, Youn Seup; Hong, Goohyeon

    2017-02-01

    Acute respiratory distress syndrome (ARDS) caused by pneumonia in patients with hematologic malignancies can be life-threatening. Extracorporeal membrane oxygenation (ECMO) is the only temporary treatment for patients with ARDS who are refractory to conventional treatment. However, the immunosuppression and coagulopathies in hematological malignancies such as lymphoma and acute leukemia are relative contraindications for ECMO, due to high risks of infection and bleeding. Here, we report a 22-year-old man with acute myeloid leukemia (AML) who developed pneumonia and ARDS during induction chemotherapy; he was treated with ECMO.

  2. Oxygen Sensing for Industrial Safety — Evolution and New Approaches

    PubMed Central

    Willett, Martin

    2014-01-01

    The requirement for the detection of oxygen in industrial safety applications has historically been met by electrochemical technologies based on the consumption of metal anodes. Products using this approach have been technically and commercially successful for more than three decades. However, a combination of new requirements is driving the development of alternative approaches offering fresh opportunities and challenges. This paper reviews some key aspects in the evolution of consumable anode products and highlights recent developments in alternative technologies aimed at meeting current and anticipated future needs in this important application. PMID:24681673

  3. Role Of Hif2α Oxygen Sensing Pathway In Bronchial Epithelial Club Cell Proliferation

    PubMed Central

    Torres-Capelli, Mar; Marsboom, Glenn; Li, Qilong Oscar Yang; Tello, Daniel; Rodriguez, Florinda Melendez; Alonso, Tamara; Sanchez-Madrid, Francisco; García-Rio, Francisco; Ancochea, Julio; Aragonés, Julián

    2016-01-01

    Oxygen-sensing pathways executed by the hypoxia-inducible factors (HIFs) induce a cellular adaptive program when oxygen supply becomes limited. However, the role of the HIF oxygen-sensing pathway in the airway response to hypoxic stress in adulthood remains poorly understood. Here we found that in vivo exposure to hypoxia led to a profound increase in bronchial epithelial cell proliferation mainly confined to Club (Clara) cells. Interestingly, this response was executed by hypoxia-inducible factor 2α (HIF2α), which controls the expression of FoxM1, a recognized proliferative factor of Club cells. Furthermore, HIF2α induced the expression of the resistin-like molecules α and β (RELMα and β), previously considered bronchial epithelial growth factors. Importantly, despite the central role of HIF2α, this proliferative response was not initiated by in vivo Vhl gene inactivation or pharmacological inhibition of prolyl hydroxylase oxygen sensors, indicating the molecular complexity of this response and the possible participation of other oxygen-sensing pathways. Club cells are principally involved in protection and maintenance of bronchial epithelium. Thus, our findings identify a novel molecular link between HIF2α and Club cell biology that can be regarded as a new HIF2α-dependent mechanism involved in bronchial epithelium adaptation to oxygen fluctuations. PMID:27150457

  4. Re(I) complex doped nanofibers for oxygen optical sensing.

    PubMed

    Hong, He; Zhu, Long; Wang, Aofang; Lu, Hongwei

    2012-12-01

    In this paper, we design and synthesize a novel diamine ligand of PTO (2-(pyridin-2-yl)-5-p-tolyl-1,3,4-oxadiazole). The crystal structure, photophysical character and electronic nature of its corresponding Re(I) complex of Re(CO)(3)(PTO)Br have been investigated in detail. Experimental data and theoretical calculation suggest that Re(CO)(3)(PTO)Br owns a long-lived yellow phosphorescence which is sensitive towards molecular oxygen. By doping Re(CO)(3)(PTO)Br into a polymer matrix of polystyrene (PS), the emission response of the resulted composite nanofibers towards molecular oxygen is studied. The optimal sample with mean diameter of 600 nm shows a maximum sensitivity of 4.14 with short response time of 14s (here sensitivity is defined as the ratio of emission intensity in pure N(2) atmosphere to that in pure O(2) atmosphere). The composite nanofibers are also found to be photostable enough to experience UV radiation.

  5. Re(I) complex doped nanofibers for oxygen optical sensing

    NASA Astrophysics Data System (ADS)

    Hong, He; Zhu, Long; Wang, Aofang; Lu, Hongwei

    2012-12-01

    In this paper, we design and synthesize a novel diamine ligand of PTO (2-(pyridin-2-yl)-5-p-tolyl-1,3,4-oxadiazole). The crystal structure, photophysical character and electronic nature of its corresponding Re(I) complex of Re(CO)3(PTO)Br have been investigated in detail. Experimental data and theoretical calculation suggest that Re(CO)3(PTO)Br owns a long-lived yellow phosphorescence which is sensitive towards molecular oxygen. By doping Re(CO)3(PTO)Br into a polymer matrix of polystyrene (PS), the emission response of the resulted composite nanofibers towards molecular oxygen is studied. The optimal sample with mean diameter of 600 nm shows a maximum sensitivity of 4.14 with short response time of 14 s (here sensitivity is defined as the ratio of emission intensity in pure N2 atmosphere to that in pure O2 atmosphere). The composite nanofibers are also found to be photostable enough to experience UV radiation.

  6. The role of high flow oxygen therapy in acute respiratory failure.

    PubMed

    Masclans, J R; Pérez-Terán, P; Roca, O

    2015-11-01

    Acute respiratory failure represents one of the most common causes of intensive care unit admission and oxygen therapy remains the first-line therapy in the management of these patients. In recent years, high-flow oxygen via nasal cannula has been described as a useful alternative to conventional oxygen therapy in patients with acute respiratory failure. High-flow oxygen via nasal cannula rapidly alleviates symptoms of acute respiratory failure and improves oxygenation by several mechanisms, including dead space washout, reduction in oxygen dilution and inspiratory nasopharyngeal resistance, a moderate positive airway pressure effect that may generate alveolar recruitment and an overall greater tolerance and comfort with the interface and the heated and humidified inspired gases. However, the experience in adults is still limited and there are no clinical guidelines to establish recommendations for their use. This article aims to review the existing evidence on the use of high-flow oxygen via nasal cannula in adults with acute respiratory failure and its possible applications, advantages and limitations.

  7. Intrarenal and urinary oxygenation during norepinephrine resuscitation in ovine septic acute kidney injury.

    PubMed

    Lankadeva, Yugeesh R; Kosaka, Junko; Evans, Roger G; Bailey, Simon R; Bellomo, Rinaldo; May, Clive N

    2016-07-01

    Norepinephrine is the principal vasopressor used to restore blood pressure in sepsis, but its effects on intrarenal oxygenation are unknown. To clarify this, we examined renal cortical, medullary, and urinary oxygenation in ovine septic acute kidney injury and the response to resuscitation with norepinephrine. A renal artery flow probe and fiberoptic probes were placed in the cortex and medulla of sheep to measure tissue perfusion and oxygenation. A probe in the bladder catheter measured urinary oxygenation. Sepsis was induced in conscious sheep by infusion of Escherichia coli for 32 hours. At 24 to 30 hours of sepsis, either norepinephrine, to restore mean arterial pressure to preseptic levels or vehicle-saline was infused (8 sheep per group). Septic acute kidney injury was characterized by a reduction in blood pressure of ∼12 mm Hg, renal hyperperfusion, and oliguria. Sepsis reduced medullary perfusion (from an average of 1289 to 628 blood perfusion units), medullary oxygenation (from 32 to 16 mm Hg), and urinary oxygenation (from 36 to 24 mm Hg). Restoring blood pressure with norepinephrine further reduced medullary perfusion to an average of 331 blood perfusion units, medullary oxygenation to 8 mm Hg and urinary oxygenation to 18 mm Hg. Cortical perfusion and oxygenation were preserved. Thus, renal medullary hypoxia caused by intrarenal blood flow redistribution may contribute to the development of septic acute kidney injury, and resuscitation of blood pressure with norepinephrine exacerbates medullary hypoxia. The parallel changes in medullary and urinary oxygenation suggest that urinary oxygenation may be a useful real-time biomarker for risk of acute kidney injury.

  8. Thickness Dependency of Thin Film Samaria Doped Ceria for Oxygen Sensing

    SciTech Connect

    Sanghavi, Rahul P.; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Jiang, Weilin; Varga, Tamas; Nachimuthu, Ponnusamy; Engelhard, Mark H.; Shutthanandan, V.; Thevuthasan, Suntharampillai; Kayani, Asghar N.; Prasad, Shalini

    2011-01-01

    High temperature oxygen sensors are widely used for exhaust gas monitoring in automobiles. This particular study explores the use of thin film single crystalline samaria doped ceria as the oxygen sensing material. Desired signal to noise ratio can be achieved in a material system with high conductivity. From previous studies it is established that 6 atomic percent samarium doping is the optimum concentration for thin film samaria doped ceria to achieve high ionic conductivity. In this study, the conductivity of the 6 atomic percent samaria doped ceria thin film is measured as a function of the sensing film thickness. Hysteresis and dynamic response of this sensing platform is tested for a range of oxygen pressures from 0.001 Torr to 100 Torr for temperatures above 673 K. An attempt has been made to understand the physics behind the thickness dependent conductivity behavior of this sensing platform by developing a hypothetical operating model and through COMSOL simulations. This study can be used to identify the parameters required to construct a fast, reliable and compact high temperature oxygen sensor.

  9. Oxygen Sensing Difluoroboron β-Diketonate Polylactide Materials with Tunable Dynamic Ranges for Wound Imaging.

    PubMed

    DeRosa, Christopher A; Seaman, Scott A; Mathew, Alexander S; Gorick, Catherine M; Fan, Ziyi; Demas, James N; Peirce, Shayn M; Fraser, Cassandra L

    2016-11-23

    Difluoroboron β-diketonate poly(lactic acid) materials exhibit both fluorescence (F) and oxygen sensitive room-temperature phosphorescence (RTP). Introduction of halide heavy atoms (Br and I) is an effective strategy to control the oxygen sensitivity in these materials. A series of naphthyl-phenyl (nbm) dye derivatives with hydrogen, bromide and iodide substituents were prepared for comparison. As nanoparticles, the hydrogen derivative was hypersensitive to oxygen (0-0.3%), while the bromide analogue was suited for hypoxia detection (0-3% O2). The iodo derivative, BF2nbm(I)PLA, showed excellent F to RTP peak separation and an 0-100% oxygen sensitivity range unprecedented for metal-free RTP emitting materials. Due to the dual emission and unconventionally long RTP lifetimes of these O2 sensing materials, a portable, cost-effective camera was used to quantify oxygen levels via lifetime and red/green/blue (RGB) ratiometry. The hypersensitive H dye was well matched to lifetime detection, simultaneous lifetime and ratiometric imaging was possible for the bromide analogue, whereas the iodide material, with intense RTP emission and a shorter lifetime, was suited for RGB ratiometry. To demonstrate the prospects of this camera/material design combination for bioimaging, iodide boron dye-PLA nanoparticles were applied to a murine wound model to detect oxygen levels. Surprisingly, wound oxygen imaging was achieved without covering (i.e. without isolating from ambient conditions, air). Additionally, would healing was monitored via wound size reduction and associated oxygen recovery, from hypoxic to normoxic. These single-component materials provide a simple tunable platform for biological oxygen sensing that can be deployed to spatially resolve oxygen in a variety of environments.

  10. Optical sensor for dual sensing of oxygen and carbon dioxide based on sensing films coated on filter paper.

    PubMed

    Chu, Cheng-Shane; Syu, Jhih-Jheng

    2017-02-01

    An optical sensor for the dual sensing of oxygen (O2) and carbon dioxide (CO2) based on sensing films coated on filter paper is proposed. Ethyl cellulose (EC) doped with platinum(II) meso-tetrakis(pentafluorophenyl)porphyrin (PtTFPP) and 7-amino-4-trifluoromethyl coumarin serve as the oxygen sensing material and reference blue emission dye for the pH indicator, respectively. The CO2 sensing layer includes the pH-sensitive fluorescent indicator 1-hydroxy-3,6,8-pyrenetrisulfonic acid trisodium salt immobilized within the EC. The O2- and CO2-sensitive materials can both be excited with a 405 nm LED, and the two emission wavelengths can be detected separately. The experimental result reveals that the optical O2 and CO2 sensors have sensitivities of IN2 /I100%O2 =22.8 and IN2 /I100%CO2 =3.6, respectively. The response times of the optical O2 sensor were 15 s upon switching from nitrogen to O2 and 41 s when moving from O2 to nitrogen (N2). The response times of the optical CO2 sensor were 7 s upon switching from 100% N2 to 100% CO2 and 39 s when moving from 100% CO2 to 100% N2. The proposed optical dual sensor can be used for the simultaneous sensing of O2 and CO2 concentrations in environmental applications.

  11. Cellular Oxygen and Nutrient Sensing in Microgravity Using Time-Resolved Fluorescence Microscopy

    NASA Technical Reports Server (NTRS)

    Szmacinski, Henryk

    2003-01-01

    Oxygen and nutrient sensing is fundamental to the understanding of cell growth and metabolism. This requires identification of optical probes and suitable detection technology without complex calibration procedures. Under this project Microcosm developed an experimental technique that allows for simultaneous imaging of intra- and inter-cellular events. The technique consists of frequency-domain Fluorescence Lifetime Imaging Microscopy (FLIM), a set of identified oxygen and pH probes, and methods for fabrication of microsensors. Specifications for electronic and optical components of FLIM instrumentation are provided. Hardware and software were developed for data acquisition and analysis. Principles, procedures, and representative images are demonstrated. Suitable lifetime sensitive oxygen, pH, and glucose probes for intra- and extra-cellular measurements of analyte concentrations have been identified and tested. Lifetime sensing and imaging have been performed using PBS buffer, culture media, and yeast cells as a model systems. Spectral specifications, calibration curves, and probes availability are also provided in the report.

  12. Two–Photon Oxygen Sensing with Quantum Dot–Porphyrin Conjugates

    PubMed Central

    Lemon, Christopher M.; Karnas, Elizabeth; Bawendi, Moungi G.; Nocera, Daniel G.

    2013-01-01

    Supramolecular assemblies of a quantum dot (QD) associated to palladium(II) porphyrins have been developed to detect oxygen (pO2) in organic solvents. Palladium porphyrins are sensitive in the 0–160 torr range, making them ideal phosphors for in vivo biological oxygen quantification. Porphyrins with meso pyridyl substituents bind to the surface of the QD to produce self–assembled nanosensors. Appreciable overlap between QD emission and porphyrin absorption features results in efficient Förster resonance energy transfer (FRET) for signal transduction in these sensors. The QD serves as a photon antenna, enhancing porphyrin emission under both one– and two–photon excitation, demonstrating that QD–palladium porphyrin conjugates may be used for oxygen sensing over physiological oxygen ranges. PMID:23978247

  13. Exercise after acute hyperbaric oxygenation: is there an ergogenic effect?

    PubMed

    Webster, A L; Syrotuik, D G; Bell, G J; Jones, R L; Bhambhani, Y; Young, M

    1998-01-01

    The purpose of this study was to determine the effects of a 1-h exposure to 2.0 atm abs (202.6 kPa) and 100% oxygen on subsequent maximal O2 consumption (VO2max), ventilation threshold (VT), lactate threshold (LT), and muscle oxygenation (%Mox) during incremental exercise to maximum on a cycle ergometer. Two baseline exercise tests (T1 and T2) were performed on separate occasions without prior exposure to hyperbaric oxygen (HBO2) and a third test (T3-HBO2) was performed after (22.5 +/- 5.6 min) HBO2 Near infared spectroscopy was used to monitor oxygenation of the left vastus lateralis muscle during T2 and T3-HBO2. No significant differences were observed between VO2max VT, or LT among any of the exercise tests. There was no significant difference in %Mox between T2 and T3-HBO2 except at 235 W where there was a significant elevation in %Mox during T3-HBO2 relative to T2. These results suggest that prior exposure to HBO2 (100% O2 at 2 atm abs for 1 h) has no ergogenic effect on subsequent incremental exercise performance.

  14. Neuroprotection of hyperbaric oxygen therapy in sub-acute traumatic brain injury: not by immediately improving cerebral oxygen saturation and oxygen partial pressure

    PubMed Central

    Zhou, Bao-chun; Liu, Li-jun; Liu, Bing

    2016-01-01

    Although hyperbaric oxygen (HBO) therapy can promote the recovery of neural function in patients who have suffered traumatic brain injury (TBI), the underlying mechanism is unclear. We hypothesized that hyperbaric oxygen treatment plays a neuroprotective role in TBI by increasing regional transcranial oxygen saturation (rSO2) and oxygen partial pressure (PaO2). To test this idea, we compared two groups: a control group with 20 healthy people and a treatment group with 40 TBI patients. The 40 patients were given 100% oxygen of HBO for 90 minutes. Changes in rSO2 were measured. The controls were also examined for rSO2 and PaO2, but received no treatment. rSO2 levels in the patients did not differ significantly after treatment, but levels before and after treatment were significantly lower than those in the control group. PaO2 levels were significantly decreased after the 30-minute HBO treatment. Our findings suggest that there is a disorder of oxygen metabolism in patients with sub-acute TBI. HBO does not immediately affect cerebral oxygen metabolism, and the underlying mechanism still needs to be studied in depth. PMID:27857747

  15. A revisit to O2 sensing and transduction in the carotid body chemoreceptors in the context of reactive oxygen species biology.

    PubMed

    Gonzalez, C; Agapito, M T; Rocher, A; Gomez-Niño, A; Rigual, R; Castañeda, J; Conde, S V; Obeso, A

    2010-12-31

    Oxygen-sensing and transduction in purposeful responses in cells and organisms is of great physiological and medical interest. All animals, including humans, encounter in their lifespan many situations in which oxygen availability might be insufficient, whether acutely or chronically, physiologically or pathologically. Therefore to trace at the molecular level the sequence of events or steps connecting the oxygen deficit with the cell responses is of interest in itself as an achievement of science. In addition, it is also of great medical interest as such knowledge might facilitate the therapeutical approach to patients and to design strategies to minimize hypoxic damage. In our article we define the concepts of sensors and transducers, the steps of the hypoxic transduction cascade in the carotid body chemoreceptor cells and also discuss current models of oxygen- sensing (bioenergetic, biosynthetic and conformational) with their supportive and unsupportive data from updated literature. We envision oxygen-sensing in carotid body chemoreceptor cells as a process initiated at the level of plasma membrane and performed by a hemoprotein, which might be NOX4 or a hemoprotein not yet chemically identified. Upon oxygen-desaturation, the sensor would experience conformational changes allosterically transmitted to oxygen regulated K+ channels, the initial effectors in the transduction cascade. A decrease in their opening probability would produce cell depolarization, activation of voltage dependent calcium channels and release of neurotransmitters. Neurotransmitters would activate the nerve endings of the carotid body sensory nerve to convey the information of the hypoxic situation to the central nervous system that would command ventilation to fight hypoxia.

  16. Remote Sensing of Dissolved Oxygen and Nitrogen in Water using Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    De Young, R.; Ganoe, R.

    2013-12-01

    The health of an estuarine ecosystem is largely driven by the abundance of dissolved oxygen and nitrogen available for maintenance of plant and animal life. An investigation was conducted to quantify the concentration of dissolved molecular oxygen and nitrogen in water by means of Raman spectroscopy. This technique is proposed for the remote sensing of dissolved oxygen in the Chesapeake Bay, which will be utilized by aircraft in order to survey large areas in real-time. A proof of principle experiment has demonstrated the ability to remotely detect dissolved oxygen and nitrogen in pure water (also Chesapeake Bay water) using a 355nm Nd:YAG laser and a simple monochromater to detect the shifted Raman oxygen and nitrogen backscattered signals at 376.2 and 387.5 nm respectively. The theoretical basis for the research, components of the experimental system, and key findings are presented. A 1.3-m water cell had an attached vertical column to house a Troll 9500 dissolved oxygen in-situ monitor (In-Situ Inc Troll 9500). The Raman oxygen signal could be calibrated with this devise. While Raman backscattered water signals are low a potential aircraft remote system was designed and will be presented.

  17. ACUTE SENSITIVITY OF JUVENILE SHORTNOSE STURGEON TO LOW DISSOLVED OXYGEN CONCENTRATIONS

    EPA Science Inventory

    Campbell, Jed G. and Larry R. Goodman. 2004. Acute Sensitivity of Juvenile Shortnose Sturgeon to Low Dissolved Oxygen Concentrations. EPA/600/J-04/175. Trans. Am. Fish. Soc. 133(3):772-776. (ERL,GB 1155).

    There is considerable concern that factors such as eutrophication, ...

  18. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2005-07-01

    A reflection mode fiber optic oxygen sensor is being developed that can operate at high temperatures for power plant applications. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Two critical materials issues are the cluster's ability to withstand high temperatures when immobilized in a porous the sol-gel support, and whether after heating to high temperatures, the sol-gel matrix maintains a high and constant permeability to oxygen to support rapid quenching of luminescence. We used a composite materials approach to prepare stable sensing layers on optical fibers. We dispersed 60 w/w% of a pre-cured sol-gel composite containing the potassium salt of molybdenum clusters (K{sub 2}Mo{sub 6}Cl{sub 14}) into a sol-gel binder solution, and established the conditions necessary for deposition of sol-gel films on optical fibers and planar substrates. The fiber sensor has an output signal of 5 nW when pumped with an inexpensive commercial 365 nm ultraviolet light emitting diode (LED). Quenching of the sensor signal by oxygen was observed up to a gas temperature of 175 C with no degradation of the oxygen permeability of the composite after high temperature cycling. On planar substrates the cluster containing composite responds within <1 second to a gas exchange from nitrogen to oxygen, indicating the feasibility of real-time oxygen detection.

  19. Facet effects of palladium nanocrystals for oxygen reduction in ionic liquids and for sensing applications

    NASA Astrophysics Data System (ADS)

    Tang, Yongan; Chi, Xiaowei; Zou, Shouzhong; Zeng, Xiangqun

    2016-03-01

    Palladium nanocrystals enclosed by {100} and {110} crystal facets, were successfully synthesized through an aqueous one-pot synthesis method. A new thermal annealing approach was developed for fabricating these palladium nanocrystals as a working electrode on a gas permeable membrane to study the facet effects of the oxygen reduction process in an ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpy][NTf2]). Results were compared with the same processes at a conventional platinum electrode. Our study shows that the structural difference between the two facets of Pd nanocrystals has little effect on the oxygen reduction process but significantly affects the oxidation process of the superoxide. It is found that the Pd{110}/IL interface can better stabilize superoxide radicals revealed by a more positive oxidation potential compared to that of Pd{100}. In addition, the analytical characteristic of utilizing both palladium nanocrystals as electrodes for oxygen sensing is comparable with a polycrystal platinum oxygen sensor, in which Pd{110} presents the best sensitivity and lowest detection limit. Our results demonstrate the facet-dependence of oxygen reduction in an ionic liquid medium and provide the fundamental information needed to guide the applications of palladium nanocrystals in electrochemical gas sensor and fuel cell research.Palladium nanocrystals enclosed by {100} and {110} crystal facets, were successfully synthesized through an aqueous one-pot synthesis method. A new thermal annealing approach was developed for fabricating these palladium nanocrystals as a working electrode on a gas permeable membrane to study the facet effects of the oxygen reduction process in an ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpy][NTf2]). Results were compared with the same processes at a conventional platinum electrode. Our study shows that the structural difference between the two facets of Pd

  20. Synthesis, characterization, photophysical and oxygen-sensing properties of a novel europium(III) complex

    NASA Astrophysics Data System (ADS)

    Feng, Nan; Xie, Jing; Zhang, Dawei

    2010-09-01

    In this paper, we report the synthesis, characterization, crystal structure, and photophysical properties of a novel Eu 3+ complex of Eu(DBM) 3IPD, where DBM = 1,3-diphenyl-propane-1,3-dione and IPD = 4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)-N,N-diphenylaniline. Its elementary application for oxygen-sensing application is also investigated by doping it into a silica matrix of MCM-41. Experimental data suggest that the 20 mg/g doped Eu(DBM) 3IPD/MCM-41 system exhibits a high sensitivity of 3.6 towards molecular oxygen with a good linear relationship of R2 = 0.9987. In addition, the 20 mg/g doped Eu(DBM) 3IPD/MCM-41 system owns a quick response of 8 s towards oxygen, along with its excellent atmosphere insensitivity and photobleaching resistance. All these results suggest that both Eu(DBM) 3IPD and Eu(DBM) 3IPD/MCM-41 systems are promising candidates for oxygen-sensing optical sensors.

  1. Remote Sensing of Dissolved Oxygen and Nitrogen in Water Using Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Ganoe, Rene; DeYoung, Russell J.

    2013-01-01

    The health of an estuarine ecosystem is largely driven by the abundance of dissolved oxygen and nitrogen available for maintenance of plant and animal life. An investigation was conducted to quantify the concentration of dissolved molecular oxygen and nitrogen in water by means of Raman spectroscopy. This technique is proposed for the remote sensing of dissolved oxygen in the Chesapeake Bay, which will be utilized by aircraft in order to survey large areas in real-time. A proof of principle system has been developed and the specifications are being honed to maximize efficiency for the final application. The theoretical criteria of the research, components of the experimental system, and key findings are presented in this report

  2. Optical oxygen sensing systems for drug discovery applications: Respirometric Screening Technology (RST)

    NASA Astrophysics Data System (ADS)

    Papkovsky, Dmitri B.; Hynes, James; Fernandes, Richard

    2005-11-01

    Quenched-fluorescence oxygen sensing allows non-chemical, reversible, real-time monitoring of molecular oxygen and rates of oxygen consumption in biological samples. Using this approach we have developed Respirometric Screening Technology (RST); a platform which facilitates the convenient analysis of cellular oxygen uptake. This in turn allows the investigation of compounds and processes which affect respiratory activity. The RST platform employs soluble phosphorescent oxygen-sensitive probes, which may be assessed in standard microtitter plates on a fluorescence plate reader. New formats of RST assays and time-resolved fluorescence detection instrumentation developed by Luxcel provide improvements in assay sensitivity, miniaturization and overall performance. RST has a diverse range of applications in drug discovery area including high throughput analysis of mitochondrial function; studies of mechanisms of toxicity and apoptosis; cell and animal based screening of compound libraries and environmental samples; and, sterility testing. RST has been successfully validated with a range of practical targets and adopted by several leading pharmaceutical companies.

  3. Reversed oxygen sensing using colloidal quantum wells towards highly emissive photoresponsive varnishes

    PubMed Central

    Lorenzon, Monica; Christodoulou, Sotirios; Vaccaro, Gianfranco; Pedrini, Jacopo; Meinardi, Francesco; Moreels, Iwan; Brovelli, Sergio

    2015-01-01

    Colloidal quantum wells combine the advantages of size-tunable electronic properties with vast reactive surfaces that could allow one to realize highly emissive luminescent-sensing varnishes capable of detecting chemical agents through their reversible emission response, with great potential impact on life sciences, environmental monitoring, defence and aerospace engineering. Here we combine spectroelectrochemical measurements and spectroscopic studies in a controlled atmosphere to demonstrate the ‘reversed oxygen-sensing’ capability of CdSe colloidal quantum wells, that is, the exposure to oxygen reversibly increases their luminescence efficiency. Spectroelectrochemical experiments allow us to directly relate the sensing response to the occupancy of surface states. Magneto-optical measurements demonstrate that, under vacuum, heterostructured CdSe/CdS colloidal quantum wells stabilize in their negative trion state. The high starting emission efficiency provides a possible means to enhance the oxygen sensitivity by partially de-passivating the particle surfaces, thereby enhancing the density of unsaturated sites with a minimal cost in term of luminescence losses. PMID:25910499

  4. Temperature Compensation of Oxygen Sensing Films Utilizing a Dynamic Dual Lifetime Calculation Technique

    PubMed Central

    Collier, Bradley B.; McShane, Michael J.

    2014-01-01

    With advances to chemical sensing, methods for compensation of errors introduced by interfering analytes are needed. In this work, a dual lifetime calculation technique was developed to enable simultaneous monitoring of two luminescence decays. Utilizing a windowed time-domain luminescence approach, the response of two luminophores is separated temporally. The ability of the dual dynamic rapid lifetime determination (DDRLD) approach to determine the response of two luminophores simultaneously was investigated through mathematical modeling and experimental testing. Modeling results indicated that lifetime predictions will be most accurate when the ratio of the lifetimes from each luminophore is at least three and the ratio of intensities is near unity. In vitro experiments were performed using a porphyrin that is sensitive to both oxygen and temperature, combined with a temperature-sensitive inorganic phosphor used for compensation of the porphyrin response. In static experiments, the dual measurements were found to be highly accurate when compared to single-luminophore measurements—statistically equivalent for the long lifetime emission and an average difference of 2% for the short lifetimes. Real-time testing with dynamic windowing was successful in demonstrating dual lifetime measurements and temperature compensation of the oxygen sensitive dye. When comparing the actual oxygen and temperature values with predictions made using a dual calibration approach, an overall difference of less than 1% was obtained. Thus, this method enables rapid, accurate extraction of multiple lifetimes without requiring computationally intense curve fitting, providing a significant advancement toward multi-analyte sensing and imaging techniques. PMID:26566384

  5. Thoracic Society of Australia and New Zealand oxygen guidelines for acute oxygen use in adults: ‘Swimming between the flags’*

    PubMed Central

    Beasley, Richard; Chien, Jimmy; Douglas, James; Eastlake, Leonie; Farah, Claude; King, Gregory; Moore, Rosemary; Pilcher, Janine; Richards, Michael; Smith, Sheree; Walters, Haydn

    2015-01-01

    The purpose of the Thoracic Society of Australia and New Zealand guidelines is to provide simple, practical evidence-based recommendations for the acute use of oxygen in adults in clinical practice. The intended users are all health professionals responsible for the administration and/or monitoring of oxygen therapy in the management of acute medical patients in the community and hospital settings (excluding perioperative and intensive care patients), those responsible for the training of such health professionals, and both public and private health care organizations that deliver oxygen therapy. PMID:26486092

  6. Molecular evolution of the metazoan PHD-HIF oxygen-sensing system.

    PubMed

    Rytkönen, Kalle T; Williams, Tom A; Renshaw, Gillian M; Primmer, Craig R; Nikinmaa, Mikko

    2011-06-01

    Metazoans rely on aerobic energy production, which requires an adequate oxygen supply. During reduced oxygen supply (hypoxia), the most profound changes in gene expression are mediated by transcription factors known as hypoxia-inducible factors (HIFs). HIF alpha proteins are commonly posttranslationally regulated by prolyl-4-hydroxylase (PHD) enzymes, which are direct "sensors" of cellular oxygen levels. We examined the molecular evolution of the metazoan PHD-HIF oxygen-sensing system by constructing complete phylogenies for PHD and HIF alpha genes and used computational tools to characterize the molecular changes underlying the functional divergence of PHD and HIF alpha duplicates. The presence of PHDs in metazoan genomes predates the emergence of HIF alphas. Our analysis revealed an unexpected diversity of PHD genes and HIF alpha sequence characteristics in invertebrates, suggesting that the simple oxygen-sensing systems of Caenorhabditis and Drosophila may not be typical of other invertebrate bilaterians. We studied the early vertebrate evolution of the system by sequencing these genes in early-diverging cartilaginous fishes, elasmobranchs. Cartilaginous fishes appear to have three paralogs of both PHD and HIF alpha. The novel sequences were used as outgroups for a detailed molecular analysis of PHD and HIF alpha duplicates in a major air-breathing vertebrate lineage, the mammals, and a major water-breathing vertebrate lineage, the teleosts. In PHDs, functionally divergent amino acid sites were detected near the HIF alpha-binding channel and beta2beta3 loop that defines its substrate specificity. In HIF alphas, more functional divergence was found in teleosts than in mammals, especially in the HIF-1 alpha PAS domain and HIF-2 alpha oxygen-dependent degradation (ODD) domains, which interact with PHDs. Overall, in the vertebrates, elevated substitution rates in the HIF-2 alpha N-terminal ODD domain, together with a functional divergence associated with the known

  7. Fiber-Based Laser Transmitter for Oxygen A-Band Spectroscopy and Remote Sensing

    NASA Technical Reports Server (NTRS)

    Stephen, Mark A.; Abshire, James B.

    2010-01-01

    A fiber-based laser transmitter has been designed for active remote-sensing spectroscopy. The transmitter uses a master-oscillator-power-amplifier (MOPA) configuration with a distributed feedback diode-laser master oscillator and an erbium-doped fiber amplifier. The output from the MOPA is frequency-doubled with a periodically poled nonlinear crystal. The utility of this single-frequency, wavelength-tunable, power-scalable laser has been demonstrated in a spectroscopic measurement of the diatomic oxygen A-band.

  8. Diversity of Magneto-Aerotactic Behaviors and Oxygen Sensing Mechanisms in Cultured Magnetotactic Bacteria

    PubMed Central

    Lefèvre, Christopher T.; Bennet, Mathieu; Landau, Livnat; Vach, Peter; Pignol, David; Bazylinski, Dennis A.; Frankel, Richard B.; Klumpp, Stefan; Faivre, Damien

    2014-01-01

    Microorganisms living in gradient environments affect large-scale processes, including the cycling of elements such as carbon, nitrogen or sulfur, the rates and fate of primary production, and the generation of climatically active gases. Aerotaxis is a common adaptation in organisms living in the oxygen gradients of stratified environments. Magnetotactic bacteria are such gradient-inhabiting organisms that have a specific type of aerotaxis that allows them to compete at the oxic-anoxic interface. They biomineralize magnetosomes, intracellular membrane-coated magnetic nanoparticles, that comprise a permanent magnetic dipole that causes the cells to align along magnetic field lines. The magnetic alignment enables them to efficiently migrate toward an optimal oxygen concentration in microaerobic niches. This phenomenon is known as magneto-aerotaxis. Magneto-aerotaxis has only been characterized in a limited number of available cultured strains. In this work, we characterize the magneto-aerotactic behavior of 12 magnetotactic bacteria with various morphologies, phylogenies, physiologies, and flagellar apparatus. We report six different magneto-aerotactic behaviors that can be described as a combination of three distinct mechanisms, including the reported (di-)polar, axial, and a previously undescribed mechanism we named unipolar. We implement a model suggesting that the three magneto-aerotactic mechanisms are related to distinct oxygen sensing mechanisms that regulate the direction of cells’ motility in an oxygen gradient. PMID:25028894

  9. Microwave-assisted synthesis of SnO₂ nanorods for oxygen gas sensing at room temperature.

    PubMed

    Azam, Ameer; Habib, Sami S; Salah, Numan A; Ahmed, Faheem

    2013-01-01

    High-quality single-crystalline SnO₂ nanorods were synthesized using a microwave-assisted solution method. The nanorods were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), ultraviolet-visible and Raman spectroscopy, Brunauer-Emmett-Teller (BET), and electrical resistance measurements. The XRD pattern indicated the formation of single-phase SnO₂ nanorods with rutile structure. FE-SEM and TEM images revealed tetragonal nanorods of about 450-500 nm in length and 60-80 nm in diameter. The nanorods showed a higher BET surface area of 288 m²/g, much higher than that of previously reported work. The Raman scattering spectra indicated a typical rutile phase of the SnO₂. The absorption spectrum showed an absorption peak centered at 340 nm, and the band-gap value was found to be 3.64 eV. The gas-sensing properties of the SnO₂ nanorods for oxygen gas with different concentrations were measured at room temperature. It was found that the value of resistance increased with the increase in oxygen gas concentration in the test chamber. The SnO₂ nanorods exhibited high sensitivity and rapid response-recovery characteristics to oxygen gas, and could detect oxygen concentration as low as 1, 3, 5, and 10 ppm.

  10. Diversity of magneto-aerotactic behaviors and oxygen sensing mechanisms in cultured magnetotactic bacteria.

    PubMed

    Lefèvre, Christopher T; Bennet, Mathieu; Landau, Livnat; Vach, Peter; Pignol, David; Bazylinski, Dennis A; Frankel, Richard B; Klumpp, Stefan; Faivre, Damien

    2014-07-15

    Microorganisms living in gradient environments affect large-scale processes, including the cycling of elements such as carbon, nitrogen or sulfur, the rates and fate of primary production, and the generation of climatically active gases. Aerotaxis is a common adaptation in organisms living in the oxygen gradients of stratified environments. Magnetotactic bacteria are such gradient-inhabiting organisms that have a specific type of aerotaxis that allows them to compete at the oxic-anoxic interface. They biomineralize magnetosomes, intracellular membrane-coated magnetic nanoparticles, that comprise a permanent magnetic dipole that causes the cells to align along magnetic field lines. The magnetic alignment enables them to efficiently migrate toward an optimal oxygen concentration in microaerobic niches. This phenomenon is known as magneto-aerotaxis. Magneto-aerotaxis has only been characterized in a limited number of available cultured strains. In this work, we characterize the magneto-aerotactic behavior of 12 magnetotactic bacteria with various morphologies, phylogenies, physiologies, and flagellar apparatus. We report six different magneto-aerotactic behaviors that can be described as a combination of three distinct mechanisms, including the reported (di-)polar, axial, and a previously undescribed mechanism we named unipolar. We implement a model suggesting that the three magneto-aerotactic mechanisms are related to distinct oxygen sensing mechanisms that regulate the direction of cells' motility in an oxygen gradient.

  11. Effect of acute and delayed hyperbaric oxygen therapy on cyanide whole blood levels during acute cyanide intoxication.

    PubMed

    Lawson-Smith, P; Jansen, E C; Hilsted, L; Johnsen, A H; Hyldegaard, O

    2011-01-01

    Cyanide and carbon monoxide, which are often found in fire victims, are toxic gases emitted from fires. Cyanide and carbon monoxide have similar molecular structure. Cyanide binds to the enzyme cytochrome oxidase a, a3 similar to carbon monoxide, thus blocking the mitochondrial respiration chain causing depletion of adenosine triphosphate. Hyperbaric oxygen (HBO2) is recommended for treating carbon monoxide poisoning. The therapeutic effect is due to a high oxygen pressure removing carbon monoxide from the cells. We hypothesise that HBO2 induces changes in whole-blood-cyanide by a competitive mechanism forcing cyanide out of cellular tissues. A rat model was developed to study this effect. Female Sprague Dawley rats were anesthetized with a fentanyl + fluanizone combination and midazolam given subcutaneously (s.c.). Rats were poisoned with 5.4 mg/kg KCN injected intra-peritoneally in Group 1 and intra-arterially in Group 2. Blood samples were taken immediately after poisoning, and at one and a half, three and five hours. Blood was drawn from a jugular vein in Group 1 and from a femoral artery in Group 2. Group 1 rats were divided into a control group of 12 rats without HBO2, 10 rats had acute HBO2 immediately after poisoning and a group of 10 rats had HBO2 one and a half hours after poisoning. Group 2 rats were divided into a control group and an acute HBO2 group, with 10 rats in both groups. Whole-blood-cyanide concentrations were measured using the Conway method based on diffusion and the subsequent formation of cyanocobalamin measured by a spectrophotometer. Results showed that whole-blood-cyanide concentration in Group 1 controls and acute HBO2 initially rose and then fell towards zero. In rats treated with delayed HBO2, the reduction in whole-blood-cyanide concentration was significantly less as compared to controls and acute HBO2-treated rats. Group 2 controls whole-blood-cyanide concentration decreased towards zero throughout the observation period. However

  12. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D. J. Osborn; Po Zhang

    2006-09-30

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications has been developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. We report on a fiber optic technique for detection of gas phase oxygen up to 100 C based on the {sup 3}O{sub 2} quenching of the luminescence from molybdenum chloride clusters, K{sub 2}Mo{sub 6}Cl{sub 14}. The inorganic sensing film is a composite of sol-gel particles embedded in a thin, oxygen permeable sol-gel binder. The particles are comprised of thermally stable, luminescent K{sub 2}Mo{sub 6}Cl{sub 14} clusters dispersed in a fully equilibrated sol-gel matrix. From 40 to 100 C, the fiber sensor switches {approx}6x in intensity in response to alternating pulses of <0.001% O2 and 21% O{sub 2} between two well defined levels with a response time of 10 s. The sensor signal is a few nW for an input pump power of 250 {micro}W. The normalized sensor signal is linear with molar oxygen concentration and fits the theoretical Stern-Volmer relationship. Although the sensitivity decreases with temperature, sensitivity at 100 C is 160 [O{sub 2}]{sup -1}. These parameters are well suited for in-situ, real-time monitoring of oxygen for industrial process control applications.

  13. Acute cocoa flavanol improves cerebral oxygenation without enhancing executive function at rest or after exercise.

    PubMed

    Decroix, Lieselot; Tonoli, Cajsa; Soares, Danusa D; Tagougui, Semah; Heyman, Elsa; Meeusen, Romain

    2016-12-01

    Acute exercise-induced improvements in cognitive function are accompanied by increased (cerebral) blood flow and increased brain-derived neurotrophic factor (BDNF) levels. Acute cocoa flavanol (CF) intake may improve cognitive function, cerebral blood flow (in humans), and BNDF levels (in animals). This study investigated (i) the effect of CF intake in combination with exercise on cognitive function and (ii) cerebral hemodynamics and BDNF in response to CF intake and exercise. Twelve healthy men participated in this randomized, double-blind, crossover study. Participants performed a cognitive task (CT) at 100 min after acute 903-mg CF or placebo (PL) intake, followed by a 30-min time-trial. Immediately after this exercise, the same CT was performed. Prefrontal near-infrared spectroscopy was applied during CT and exercise to measure changes in oxygenated (ΔHbO2), deoxygenated (ΔHHb), and total haemoglobin (ΔHbtot) and blood samples were drawn and analyzed for BDNF. Reaction time was faster postexercise, but was not influenced by CF. ΔHbO2 during the resting CT was increased by CF, compared with PL. ΔHbO2, ΔHHb, and ΔHbtot increased in response to exercise without any effect of CF. During the postexercise cognitive task, there were no hemodynamic differences between CF or PL. Serum BDNF was increased by exercise, but was not influenced by CF. In conclusion, at rest, CF intake increased cerebral oxygenation, but not BDNF concentrations, and no impact on executive function was detected. This beneficial effect of CF on cerebral oxygenation at rest was overruled by the strong exercise-induced increases in cerebral perfusion and oxygenation.

  14. Extracorporeal Membrane Oxygenation Outcomes in Acute Respiratory Distress Treatment: Case Study in a Chinese Referral Center

    PubMed Central

    Huang, Lei; Li, Tong; Xu, Lei; Hu, Xiao-min; Duan, Da-wei; Li, Zhi-bo; Gao, Xin-jing; Li, Jun; Wu, Peng; Liu, Ying-Wu

    2017-01-01

    Background No definitive conclusions have been drawn from the available data about the utilization of extracorporeal membrane oxygenation (ECMO) to treat severe acute respiratory distress syndrome (ARDS). The aim of this study was to review our center’s experience with ECMO and determine predictors of outcome from our Chinese center. Material/Methods We retrospectively analyzed a total of 23 consecutive candidates who fulfilled the study entry criteria between January 2009 and December 2015. Detailed clinical data, ECMO flow, and respiratory parameters before and after the introduction of ECMO were compared among in-hospital survivors and nonsurvivors; factors associated with mortality were investigated. Results Hemodynamics and oxygenation parameters were significantly improved after ECMO initiation. Thirteen patients survived to hospital discharge. Univariate correlation analysis demonstrated that APACHE II score (r=−0.463, p=0.03), acute kidney injury (r=−0.574, p=0.005), membrane oxygenator replacement (r=−0.516, p=0.014) and total length of hospital stay (r=0.526, p=0.012) were significantly correlated with survival to hospital discharge, and that the evolution of the levels of urea nitrogen, platelet, and fibrinogen may help to determine patient prognosis. Sixteen patients referred for ECMO from an outside hospital were successfully transported to our institution by ambulance, including seven transported under ECMO support. The survival rate of the ECMO-transport group was comparable to the conventional transport or the non-transport group (both p=1.000). Conclusions ECMO is an effective alternative option for severe ARDS. APACHE II score on admission, onset of acute kidney injury, and membrane oxygenator replacement, and the evolution of levels of urea nitrogen, platelet, and fibrinogen during hospitalization may help to determine the in-hospital patient prognosis. By establishing a well-trained mobile ECMO team, a long-distance, inter

  15. Extracorporeal Membrane Oxygenation Outcomes in Acute Respiratory Distress Treatment: Case Study in a Chinese Referral Center.

    PubMed

    Huang, Lei; Li, Tong; Xu, Lei; Hu, Xiao-Min; Duan, Da-Wei; Li, Zhi-Bo; Gao, Xin-Jing; Li, Jun; Wu, Peng; Liu, Ying-Wu

    2017-02-10

    BACKGROUND No definitive conclusions have been drawn from the available data about the utilization of extracorporeal membrane oxygenation (ECMO) to treat severe acute respiratory distress syndrome (ARDS). The aim of this study was to review our center's experience with ECMO and determine predictors of outcome from our Chinese center. MATERIAL AND METHODS We retrospectively analyzed a total of 23 consecutive candidates who fulfilled the study entry criteria between January 2009 and December 2015. Detailed clinical data, ECMO flow, and respiratory parameters before and after the introduction of ECMO were compared among in-hospital survivors and nonsurvivors; factors associated with mortality were investigated. RESULTS Hemodynamics and oxygenation parameters were significantly improved after ECMO initiation. Thirteen patients survived to hospital discharge. Univariate correlation analysis demonstrated that APACHE II score (r=-0.463, p=0.03), acute kidney injury (r=-0.574, p=0.005), membrane oxygenator replacement (r=-0.516, p=0.014) and total length of hospital stay (r=0.526, p=0.012) were significantly correlated with survival to hospital discharge, and that the evolution of the levels of urea nitrogen, platelet, and fibrinogen may help to determine patient prognosis. Sixteen patients referred for ECMO from an outside hospital were successfully transported to our institution by ambulance, including seven transported under ECMO support. The survival rate of the ECMO-transport group was comparable to the conventional transport or the non-transport group (both p=1.000). CONCLUSIONS ECMO is an effective alternative option for severe ARDS. APACHE II score on admission, onset of acute kidney injury, and membrane oxygenator replacement, and the evolution of levels of urea nitrogen, platelet, and fibrinogen during hospitalization may help to determine the in-hospital patient prognosis. By establishing a well-trained mobile ECMO team, a long-distance, inter-hospital transport

  16. Linear oxygen-sensing response from a rhenium complex induced by heavy atom: synthesis, characterization, photophysical study and sensing performance.

    PubMed

    Wan, Pu; Zhao, Lun; Wang, Lisha; Xu, Guangyang

    2013-08-01

    In this paper, we synthesized a Br-containing ligand of 2-(4-bromophenyl)-5-(pyridin-2-yl)-1,3,4-oxadiazole and its corresponding Re(I) complex. Their synthesis, characterization, single crystal structure, electronic transitions and photophysical property were presented and discussed in detail. This Re(I) complex was found to be a yellow emitter with slim π→π* radiative decay contribution, and its emission was also found to be sensitive towards O2. By doping this Re(I) complex into a polymer matrix, the oxygen-sensing performance of the resulted composite nanofibers was also investigated. Owing to the porous structure of the supporting matrix, the optimal sample gave the highest sensitivity of 3.91 with short response time of only 9 s. In addition, the linearity of the Stern-Volmer plots was greatly improved due to the highly pure emissive center triggered by heavy-atom turbulence effect from Br atom, as indicted by theoretical calculation result.

  17. Linear oxygen-sensing response from a rhenium complex induced by heavy atom: Synthesis, characterization, photophysical study and sensing performance

    NASA Astrophysics Data System (ADS)

    Pu, Wan; Lun, Zhao; Lisha, Wang; Guangyang, Xu

    2013-08-01

    In this paper, we synthesized a Br-containing ligand of 2-(4-bromophenyl)-5-(pyridin-2-yl)-1,3,4-oxadiazole and its corresponding Re(I) complex. Their synthesis, characterization, single crystal structure, electronic transitions and photophysical property were presented and discussed in detail. This Re(I) complex was found to be a yellow emitter with slim π → π* radiative decay contribution, and its emission was also found to be sensitive towards O2. By doping this Re(I) complex into a polymer matrix, the oxygen-sensing performance of the resulted composite nanofibers was also investigated. Owing to the porous structure of the supporting matrix, the optimal sample gave the highest sensitivity of 3.91 with short response time of only 9 s. In addition, the linearity of the Stern-Volmer plots was greatly improved due to the highly pure emissive center triggered by heavy-atom turbulence effect from Br atom, as indicted by theoretical calculation result.

  18. Caffeine protects human skin fibroblasts from acute reactive oxygen species-induced necrosis.

    PubMed

    Silverberg, Jonathan I; Patel, Mital; Brody, Neil; Jagdeo, Jared

    2012-11-01

    Oxidative damage by reactive oxygen species (ROS) plays a major role in aging and carcinogenesis. Little is known about either the effects of acute ROS in necrosis and inflammation of skin or the therapeutic agents for prevention and treatment. Previously, our laboratory identified caffeine as an inhibitor of hydrogen peroxide (H2O2)-generated lipid peroxidation products in human skin fibroblasts. Here, we study effects of caffeine on acute ROS-mediated necrosis. Human skin fibroblasts were incubated with caffeine, followed by H2O2 challenge. Flow cytometry was used to analyze cell morphology, counts, apoptosis and necrosis, and ROS. We found that caffeine protects from H2O2 cell damage at lower (0.01 mM) and intermediate (0.1 mM) doses. The beneficial effects of caffeine appear to be mediated by a mechanism other than antioxidant function.

  19. Should hyperbaric oxygen be used to treat the pregnant patient for acute carbon monoxide poisoning

    SciTech Connect

    Van Hoesen, K.B.; Camporesi, E.M.; Moon, R.E.; Hage, M.L.; Piantadosi, C.A. )

    1989-02-17

    Carbon monoxide (CO) is the leading cause of death due to poisoning. Although uncommon, CO poisoning does occur during pregnancy and can result in fetal mortality and neurological malformations in fetuses who survive to term. Uncertainty arises regarding the use of hyperbaric oxygen (HBO) as a treatment for the pregnant patient because of possible adverse effects on the fetus that could be induced by oxygen at high partial pressures. While the dangers of hyperoxia to the fetus have been demonstrated in animal models, careful review of animal studies and human clinical experience indicates that the short duration of hyperoxic exposure attained during HBO therapy for CO poisoning can be tolerated by the fetus in all stages of pregnancy and reduces the risk of death or deformity to the mother and fetus. A case is presented of acute CO poisoning during pregnancy that was successfully treated with HBO. Recommendations are suggested for the use of HBO during pregnancy.

  20. Oxygen saturation changes in the optic nerve head during acute intraocular pressure elevation in monkeys

    NASA Astrophysics Data System (ADS)

    Khoobehi, Bahram; Kawano, Hiroyuki; Ning, Jinfeng; Burgoyne, Claude F.; Rice, David A.; Khan, Fareeha; Thompson, Hilary W.; Beach, James M.

    2009-02-01

    Background and Objective: To evaluate the effect of an acute elevated intraocular pressure (IOP) on oxygen saturation of structures of the optic nerve head. Study Design/Materials and Methods: In the cynomolgus monkey eye, IOP was set to 10 mm Hg, and then raised to 30, 45, and 55 mm Hg. The ONH and overlying vessels were imaged using a fundus camera attached to a hyperspectral imaging system (HSI) at 10 and 30 minutes after IOP elevation. Results: Raising IOP from 10 to 30 mm Hg did not significantly (P < 0.0001) change saturation in vessels or ONH tissue structures but at 55 mm Hg, all structures showed significant reduction. Conclusions: Quantitative assay of the blood oxygen saturation in structures on the surface and overlying the optic nerve head is possible using hyperspectral imaging techniques.

  1. Ataxia in acute mountain sickness does not improve with short-term oxygen inhalation.

    PubMed

    Baumgartner, Ralf W; Bärtsch, Peter

    2002-01-01

    Stability of stance declines at high altitude in subjects with and without acute mountain sickness (AMS), suggesting that postural ataxia might result from different hypoxia-related mechanisms than those causing the signs and symptoms of AMS. The aim of this study was to determine whether short-term oxygen inhalation improves stability of stance assessed by static posturography and/or the symptoms of AMS. Twenty male volunteers with cerebral AMS scores above 0.70 were investigated the first or second morning of their stay at an altitude of 4559 m. Posturographic parameters remained unchanged, whereas cerebral AMS scores decreased (p < 0.001) after inhalation of 3 L/min of oxygen for at least 10 min. We conclude that ataxia of stance assessed by posturography may result from different hypoxia-triggered mechanisms that need more time for recovery than those causing AMS.

  2. Molybdenum chloride incorporated sol-gel materials for oxygen sensing above room temperature

    NASA Astrophysics Data System (ADS)

    Osborn, D. J., III

    Maximizing the efficiency of the combustion process requires the ability to sense oxygen levels over a broad range of concentrations with fast response times under rapidly varying conditions of pressure and temperature to maintain the correct fuel/oxygen ratio in real-time. Quenching of the luminescence from organometallic compounds by oxygen has been used to develop a number of fiber-based sensors. A major drawback of these organometallic indicators for combustion applications is that the chromophores degrade with time, have a limited operational temperature range, typically room temperature +/-25°C, and lack long-term reliability. This work investigates luminescent molybdenum clusters based on Mo6Cl12 were as replacements for organometallic indicators. A study of the high temperature stability of Mo6Cl 12 in air revealed irreversible changes in the optical absorption spectrum at T >250°C and a loss of the red luminescence characteristic of the pristine clusters. Thermal aging experiments run in air and under nitrogen point to oxidation of the clusters as the cause of the change in optical properties. X-ray powder diffraction measurements on samples annealed at 300°C under controlled conditions are consistent with oxidation of Mo6Cl 12 to form MoO3. Optical and thermal aging experiments show that K2Mo6Cl14•1H2O, the alkali metal salt of Mo6Cl12, has higher thermal stability and remains luminescent after long-term aging in air at 280°C. Methods were developed for depositing K2Mo6Cl14•1H 2O-incorporated sol--gel films on planar and optical fiber substrates by dip coating and spray coating. The mechanical properties of the films depended on the film thickness; thin films were stable, but cracks often formed in the thicker films needed for sensors. This problem was addressed using two strategies: altering the components of the sol--gel solutions used to embed the clusters and by devising a composite approach to sensing layers where a slurry of fully cured sol

  3. A green-emitting Cu complex for oxygen-sensing purpose: Synthesis, characterization and photophysical features

    NASA Astrophysics Data System (ADS)

    Hui, Han; Wei, Li; Zhentao, Liu; Xiangen, Han

    2015-05-01

    In the present work, a green-emitting Cu(I) complex [Cu(BT-Et)(POP)]BF4 was synthesized and fully characterized, where BT-Et = 4-(1-ethyl-1H-benzo[d]imidazol-2-yl)thiazole, POP = bis(2-(diphenylphosphanyl)phenyl) ether, respectively. An ethyl group was connected onto the diamine ligand to breach π-π attraction within solid [Cu(BT-Et)(POP)]BF4, favoring O2 molecule attack and sensitivity improvement. Its molecular identity was confirmed by single crystal analysis and theoretical calculation. [Cu(BT-Et)(POP)]BF4 emitted long-lived green emission peaking at 521 nm upon photoexcitation which was vulnerable towards O2 molecule, making itself a potential oxygen sensing material. [Cu(BT-Et)(POP)]BF4 was then doped into a silica supporting matrix MCM-41. The resulting composite samples showed sensing behavior towards O2 molecule, with short response time of 10 s and sensitivity of 5.56.

  4. Early non-destructive biofouling detection and spatial distribution: Application of oxygen sensing optodes.

    PubMed

    Farhat, N M; Staal, M; Siddiqui, A; Borisov, S M; Bucs, Sz S; Vrouwenvelder, J S

    2015-10-15

    Biofouling is a serious problem in reverse osmosis/nanofiltration (RO/NF) applications, reducing membrane performance. Early detection of biofouling plays an essential role in an adequate anti-biofouling strategy. Presently, fouling of membrane filtration systems is mainly determined by measuring changes in pressure drop, which is not exclusively linked to biofouling. Non-destructive imaging of oxygen concentrations (i) is specific for biological activity of biofilms and (ii) may enable earlier detection of biofilm accumulation than pressure drop. The objective of this study was to test whether transparent luminescent planar O2 optodes, in combination with a simple imaging system, can be used for early non-destructive biofouling detection. This biofouling detection is done by mapping the two-dimensional distribution of O2 concentrations and O2 decrease rates inside a membrane fouling simulator (MFS). Results show that at an early stage, biofouling development was detected by the oxygen sensing optodes while no significant increase in pressure drop was yet observed. Additionally, optodes could detect spatial heterogeneities in biofouling distribution at a micro scale. Biofilm development started mainly at the feed spacer crossings. The spatial and quantitative information on biological activity will lead to better understanding of the biofouling processes, contributing to the development of more effective biofouling control strategies.

  5. Composite Hydrogels with Engineered Microdomains for Optical Glucose Sensing at Low Oxygen Conditions

    PubMed Central

    Bornhoeft, Lindsey R.; Biswas, Aniket; McShane, Michael J.

    2017-01-01

    There is a growing need for advanced tools that enable frequent monitoring of biomarkers for precision medicine. In this work, we present a composite hydrogel-based system providing real-time optical bioanalyte monitoring. The responsive material, alginate-in-alginate (AnA), is comprised of an alginate hydrogel with embedded bioactive, nanofilm-coated phosphorescent microdomains; palladium tetracarboxyphenylporphyrin serves as an optical indicator, glucose oxidase as a model enzyme, and layer-by-layer deposited polyelectrolyte multilayers (PEMs) as the diffusion barrier. Glutaraldehyde crosslinking of the nanofilms resulted in a dramatic reduction in glucose diffusion (179%) while oxygen transport was not significantly affected. The responses of the AnA hydrogels to step changes of glucose at both ambient and physiological oxygen levels were evaluated, revealing controlled tuning of sensitivity and dynamic range. Stability, assessed by alternately exposing the responsive AnA hydrogels to extremely high and zero glucose concentrations, resulted in no significant difference in the response over 20 cycles. These AnA hydrogels represent an attractive approach to biosensing based on biocompatible materials that may be used as minimally-invasive, implantable devices capable of optical interrogation. The model glucose-responsive composite material studied in this work will serve as a template that can be translated for sensing additional analytes (e.g., lactate, urea, pyruvate, cholesterol) and can be used for monitoring other chronic conditions. PMID:28117762

  6. Oxygen Sensing Mesenchymal Progenitors Promote Neo-Vasculogenesis in a Humanized Mouse Model In Vivo

    PubMed Central

    Hofmann, Nicole A.; Ortner, Anna; Jacamo, Rodrigo O.; Reinisch, Andreas; Schallmoser, Katharina; Rohban, Rokhsareh; Etchart, Nathalie; Fruehwirth, Margareta; Beham-Schmid, Christine; Andreeff, Michael; Strunk, Dirk

    2012-01-01

    Despite insights into the molecular pathways regulating hypoxia-induced gene expression, it is not known which cell types accomplish oxygen sensing during neo-vasculogenesis. We have developed a humanized mouse model of endothelial and mesenchymal progenitor co-transplantation to delineate the cellular compartments responsible for hypoxia response during vasculogenesis. Mesenchymal stem/progenitor cells (MSPCs) accumulated nuclear hypoxia-inducible transcription factor (HIF)-1α earlier and more sensitively than endothelial colony forming progenitor cells (ECFCs) in vitro and in vivo. Hypoxic ECFCs showed reduced function in vitro and underwent apoptosis within 24h in vivo when used without MSPCs. Surprisingly, only in MSPCs did pharmacologic or genetic inhibition of HIF-1α abrogate neo-vasculogenesis. HIF deletion in ECFCs caused no effect. ECFCs could be rescued from hypoxia-induced apoptosis by HIF-competent MSPCs resulting in the formation of patent perfused human vessels. Several angiogenic factors need to act in concert to partially substitute mesenchymal HIF-deficiency. Results demonstrate that ECFCs require HIF-competent vessel wall progenitors to initiate vasculogenesis in vivo and to bypass hypoxia-induced apoptosis. We describe a novel mechanistic role of MSPCs as oxygen sensors promoting vasculogenesis thus underscoring their importance for the development of advanced cellular therapies. PMID:22970226

  7. Proteomic analysis reveals diverse proline hydroxylation-mediated oxygen-sensing cellular pathways in cancer cells

    PubMed Central

    Liu, Bing; Gao, Yankun; Ruan, Hai-Bin; Chen, Yue

    2016-01-01

    Proline hydroxylation is a critical cellular mechanism regulating oxygen-response pathways in tumor initiation and progression. Yet, its substrate diversity and functions remain largely unknown. Here, we report a system-wide analysis to characterize proline hydroxylation substrates in cancer cells using an immunoaffinity-purification assisted proteomics strategy. We identified 562 sites from 272 proteins in HeLa cells. Bioinformatic analysis revealed that proline hydroxylation substrates are significantly enriched with mRNA processing and stress-response cellular pathways with canonical and diverse flanking sequence motifs. Structural analysis indicates a significant enrichment of proline hydroxylation participating in the secondary structure of substrate proteins. Our study identified and validated Brd4, a key transcription factor, as a novel proline hydroxylation substrate. Functional analysis showed that the inhibition of proline hydroxylation pathway significantly reduced the proline hydroxylation abundance on Brd4 and affected Brd4-mediated transcriptional activity as well as cell proliferation in AML leukemia cells. Taken together, our study identified a broad regulatory role of proline hydroxylation in cellular oxygen-sensing pathways and revealed potentially new targets that dynamically respond to hypoxia microenvironment in tumor cells. PMID:27764789

  8. Composite Hydrogels with Engineered Microdomains for Optical Glucose Sensing at Low Oxygen Conditions.

    PubMed

    Bornhoeft, Lindsey R; Biswas, Aniket; McShane, Michael J

    2017-01-22

    There is a growing need for advanced tools that enable frequent monitoring of biomarkers for precision medicine. In this work, we present a composite hydrogel-based system providing real-time optical bioanalyte monitoring. The responsive material, alginate-in-alginate (AnA), is comprised of an alginate hydrogel with embedded bioactive, nanofilm-coated phosphorescent microdomains; palladium tetracarboxyphenylporphyrin serves as an optical indicator, glucose oxidase as a model enzyme, and layer-by-layer deposited polyelectrolyte multilayers (PEMs) as the diffusion barrier. Glutaraldehyde crosslinking of the nanofilms resulted in a dramatic reduction in glucose diffusion (179%) while oxygen transport was not significantly affected. The responses of the AnA hydrogels to step changes of glucose at both ambient and physiological oxygen levels were evaluated, revealing controlled tuning of sensitivity and dynamic range. Stability, assessed by alternately exposing the responsive AnA hydrogels to extremely high and zero glucose concentrations, resulted in no significant difference in the response over 20 cycles. These AnA hydrogels represent an attractive approach to biosensing based on biocompatible materials that may be used as minimally-invasive, implantable devices capable of optical interrogation. The model glucose-responsive composite material studied in this work will serve as a template that can be translated for sensing additional analytes (e.g., lactate, urea, pyruvate, cholesterol) and can be used for monitoring other chronic conditions.

  9. Acute Supramaximal Exercise Increases the Brain Oxygenation in Relation to Cognitive Workload

    PubMed Central

    Bediz, Cem Seref; Oniz, Adile; Guducu, Cagdas; Ural Demirci, Enise; Ogut, Hilmi; Gunay, Erkan; Cetinkaya, Caner; Ozgoren, Murat

    2016-01-01

    Single bout of exercise can improve the performance on cognitive tasks. However, cognitive responses may be controversial due to different type, intensity, and duration of exercise. In addition, the mechanism of the effect of acute exercise on brain is still unclear. This study was aimed to investigate the effects of supramaximal exercise on cognitive tasks by means of brain oxygenation monitoring. The brain oxygenation of Prefrontal cortex (PFC) was measured on 35 healthy male volunteers via functional near infrared spectroscopy (fNIRS) system. Subjects performed 2-Back test before and after the supramaximal exercise wingate anerobic test (WAnT) lasting 30-s on cycle ergometer. The PFC oxygenation change evaluation revealed that PFC oxygenation rise during post-exercise 2-Back task was considerably higher than those in pre-exercise 2-Back task. In order to describe the relationship between oxygenation change and exercise performance, subjects were divided into two groups as high performers (HP) and low performers (LP) according to their peak power values (PP) obtained from the supramaximal test. The oxy-hemoglobin (oxy-Hb) values were compared between pre- and post-exercise conditions within subjects and also between subjects according to peak power. When performers were compared, in the HP group, the oxy-Hb values in post-exercise 2-Back test were significantly higher than those in pre-exercise 2-Back test. HP had significantly higher post-exercise oxy-Hb change (Δ) than those of LP. In addition, PP of the total group were significantly correlated with Δoxy-Hb.The key findings of the present study revealed that acute supramaximal exercise has an impact on the brain oxygenation during a cognitive task. Also, the higher the anerobic PP describes the larger the oxy-Hb response in post-exercise cognitive task. The current study also demonstrated a significant correlation between peak power (exercise load) and post-exercise hemodynamic responses (oxy-, deoxy- and

  10. High sensitivity and accuracy dissolved oxygen (DO) detection by using PtOEP/poly(MMA-co-TFEMA) sensing film.

    PubMed

    Zhang, Ke; Zhang, Honglin; Wang, Ying; Tian, Yanqing; Zhao, Jiupeng; Li, Yao

    2017-01-05

    Fluorinated acrylate polymer has received great interest in recent years due to its extraordinary characteristics such as high oxygen permeability, good stability, low surface energy and refractive index. In this work, platinum octaethylporphyrin/poly(methylmethacrylate-co-trifluoroethyl methacrylate) (PtOEP/poly(MMA-co-TFEMA)) oxygen sensing film was prepared by the immobilizing of PtOEP in a poly(MMA-co-TFEMA) matrix and the technological readiness of optical properties was established based on the principle of luminescence quenching. It was found that the oxygen-sensing performance could be improved by optimizing the monomer ratio (MMA/TFEMA=1:1), tributylphosphate(TBP, 0.05mL) and PtOEP (5μg) content. Under this condition, the maximum quenching ratio I0/I100 of the oxygen sensing film is obtained to be about 8.16, Stern-Volmer equation is I0/I=1.003+2.663[O2] (R(2)=0.999), exhibiting a linear relationship, good photo-stability, high sensitivity and accuracy. Finally, the synthesized PtOEP/poly(MMA-co-TFEMA) sensing film was used for DO detection in different water samples.

  11. High sensitivity and accuracy dissolved oxygen (DO) detection by using PtOEP/poly(MMA-co-TFEMA) sensing film

    NASA Astrophysics Data System (ADS)

    Zhang, Ke; Zhang, Honglin; Wang, Ying; Tian, Yanqing; Zhao, Jiupeng; Li, Yao

    2017-01-01

    Fluorinated acrylate polymer has received great interest in recent years due to its extraordinary characteristics such as high oxygen permeability, good stability, low surface energy and refractive index. In this work, platinum octaethylporphyrin/poly(methylmethacrylate-co-trifluoroethyl methacrylate) (PtOEP/poly(MMA-co-TFEMA)) oxygen sensing film was prepared by the immobilizing of PtOEP in a poly(MMA-co-TFEMA) matrix and the technological readiness of optical properties was established based on the principle of luminescence quenching. It was found that the oxygen-sensing performance could be improved by optimizing the monomer ratio (MMA/TFEMA = 1:1), tributylphosphate(TBP, 0.05 mL) and PtOEP (5 μg) content. Under this condition, the maximum quenching ratio I0/I100 of the oxygen sensing film is obtained to be about 8.16, Stern-Volmer equation is I0/I = 1.003 + 2.663[O2] (R2 = 0.999), exhibiting a linear relationship, good photo-stability, high sensitivity and accuracy. Finally, the synthesized PtOEP/poly(MMA-co-TFEMA) sensing film was used for DO detection in different water samples.

  12. Regional brain blood flow and cerebral hemispheric oxygen consumption during acute hypoxaemia in the llama fetus

    PubMed Central

    Llanos, Aníbal J; Riquelme, Raquel A; Sanhueza, Emilia M; Herrera, Emilio; Cabello, Gertrudis; Giussani, Dino A; Parer, Julian T

    2002-01-01

    Unlike fetal animals of lowland species, the llama fetus does not increase its cerebral blood flow during an episode of acute hypoxaemia. This study tested the hypothesis that the fetal llama brain maintains cerebral hemispheric O2 consumption by increasing cerebral O2 extraction rather than decreasing cerebral oxygen utilisation during acute hypoxaemia. Six llama fetuses were surgically instrumented under general anaesthesia at 217 days of gestation (term ca 350 days) with vascular and amniotic catheters in order to carry out cardiorespiratory studies. Following a control period of 1 h, the llama fetuses underwent 3 × 20 min episodes of progressive hypoxaemia, induced by maternal inhalational hypoxia. During basal conditions and during each of the 20 min of hypoxaemia, fetal cerebral blood flow was measured with radioactive microspheres, cerebral oxygen extraction was calculated, and fetal cerebral hemispheric O2 consumption was determined by the modified Fick principle. During hypoxaemia, fetal arterial O2 tension and fetal pH decreased progressively from 24 ± 1 to 20 ± 1 Torr and from 7.36 ± 0.01 to 7.33 ± 0.01, respectively, during the first 20 min episode, to 16 ± 1 Torr and 7.25 ± 0.05 during the second 20 min episode and to 14 ± 1 Torr and 7.21 ± 0.04 during the final 20 min episode. Fetal arterial partial pressure of CO2 (Pa,CO2, 42 ± 2 Torr) remained unaltered from baseline throughout the experiment. Fetal cerebral hemispheric blood flow and cerebral hemispheric oxygen extraction were unaltered from baseline during progressive hypoxaemia. In contrast, a progressive fall in fetal cerebral hemispheric oxygen consumption occurred during the hypoxaemic challenge. In conclusion, these data do not support the hypothesis that the fetal llama brain maintains cerebral hemispheric O2 consumption by increasing cerebral hemispheric O2 extraction. Rather, the data show that in the llama fetus, a reduction in cerebral hemispheric metabolism occurs during acute

  13. Human autonomic activity and its response to acute oxygen supplement after high altitude acclimatization.

    PubMed

    Bao, Xuping; Kennedy, Brian P; Hopkins, Susan R; Bogaard, Harm J; Wagner, Peter D; Ziegler, Michael G

    2002-11-29

    It is well established that after acclimatization at high altitude, many sympathetic pathways are hyperactive yet heart rate (HR) remains unchanged. In this study, we attempted to determine if this unchanged heart rate is due to compensatory mechanisms such as changes in parasympathetic activity or levels of receptors for autonomic neurotransmitters. We also examined the role played by hypoxia in these autonomic adaptations to high altitude. Three experiments were carried out on five healthy lowlanders both at sea level (SL) and after 2 weeks of acclimatization at 3800 m (Post-Ac) with: (a) placebo (control); (b) acute beta-adrenergic receptor blockade by propranolol (PRO), or (c) acute parasympathetic receptor blockade by glycopyrrolate (GLY). Compared with SL control values, post-Ac venous norepinephrine (NE) and dopamine increased by 96% (p < 0.001) and 55% (p < 0.05), but epinephrine and HR did not change. PRO resulted in a smaller decrease in HR (bpm) Post-Ac than at SL (15 +/- 6 vs. 21 +/- 6, p < 0.05), while GLY caused a greater increase in HR Post-Ac than at SL (59 +/- 8 vs. 45 +/- 6, p < 0.05). Breathing oxygen at SL concentration while at altitude did not decrease NE, or alter the effect of PRO on HR, but reduced the chronotropic effect of GLY by 14% (p < 0.05). These results suggest that after acclimatization to altitude, increased parasympathetic neurotransmitter release and decreased beta-adenoreceptor activity account for the unchanged HR despite enhanced sympathetic activity. Acute oxygen replacement rapidly counteracted the parasympathetic, but not sympathetic hyperactivity that occurs at high altitude.

  14. Early Extracorporeal Membrane Oxygenation Support for 5-Fluorouracil-induced Acute Heart Failure with Cardiogenic Shock.

    PubMed

    Höllriegel, Robert; Fischer, Julia; Schuler, Gerhard

    2014-01-01

    A 50-year-old man with no previous history of cardiovascular disease or risk factors was admitted for syncope and orthopnea. Importantly, he underwent recent chemotherapy with 5-fluorouracil (5-FU) until 1 day before his acute presentation. In the emergency room, patient developed asystole and was successfully resuscitated for 2 min. At coronary angiography, no signs of coronary artery disease were detectable, but transthoracic echocardiography showed a severely decreased left-ventricular systolic function. Due to the progressive cardiogenic shock, an extracorporeal membrane oxygenation (ECMO) support was used as bridge-to-recovery and to avoid the use of sympathomimetics with their known disadvantages. On ECMO support, hemodynamic stabilization was evident and medical heart failure treatment was commenced. Left-ventricular function recovered to normal values within a short period of time. Cardiac complications after chemotherapy with 5-FU are not rare and should be taken into consideration even in acute heart failure with cardiogenic shock. ECMO as the most potent form of acute cardiorespiratory support enables complete relief of cardiac workload and therefore recovery of cardiac function.

  15. Interdisciplinary Peripartum Management of Acute Respiratory Distress Syndrome with Extracorporeal Membrane Oxygenation – a Case Report and Literature Review

    PubMed Central

    Weyrich, J.; Bogdanski, R.; Ortiz, J. U.; Kuschel, B.; Schneider, K. T. M.; Lobmaier, S. M.

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is increasingly used for the management of acute severe cardiac and respiratory failure. One of the indications is acute respiratory distress syndrome (ARDS) for which, in some severe cases, ECMO represents the only possibility to save lives. We report on the successful long-term use of ECMO in a postpartum patient with recurrent pulmonary decompensation after peripartum uterine rupture with extensive blood loss. PMID:27065489

  16. Roles of Proton-Sensing Receptors in the Transition from Acute to Chronic Pain.

    PubMed

    Sun, W H; Chen, C C

    2016-02-01

    Chronic pain, when not effectively treated, is a leading health and socioeconomic problem and has a harmful effect on all aspects of health-related quality of life. Therefore, understanding the molecular mechanism of how pain transitions from the acute to chronic phase is essential for developing effective novel analgesics. Accumulated evidence has shown that the transition from acute to chronic pain is determined by a cellular signaling switch called hyperalgesic priming, which occurs in primary nociceptive afferents. The hyperalgesic priming is triggered by inflammatory mediators and is involved in a signal switch from protein kinase A (PKA) to protein kinase Cε (PKCε) located in both isolectin B4 (IB4)-positive (nonpeptidergic) and IB4-negative (peptidergic) nociceptors. Acidosis may be the decisive factor regulating the PKA-to-PKCε signal switch in a proton-sensing G-protein-coupled receptor-dependent manner. Protons can also induce the hyperalgesic priming in IB4-negative muscle nociceptors in a PKCε-independent manner. Acid-sensing ion channel 3 (ASIC3) and transient receptor potential/vanilloid receptor subtype 1 (TRPV1) are 2 major acid sensors involved in the proton-induced hyperalgesic priming. The proton-induced hyperalgesic priming in muscle afferents can be prevented by a substance P-mediated signaling pathway. In this review, we summarize the factors that modulate hyperalgesic priming in both IB4-positive and IB4-negative nociceptors and discuss the role of acid signaling in inflammatory and noninflammatory pain as well as orofacial muscle pain.

  17. Cellular Oxygen Sensing: Crystal Structure of Hypoxia-Inducible Factor Prolyl Hydroxylase (PHD2)

    SciTech Connect

    McDonough,M.; Li, V.; Flashman, E.; Chowdhury, R.; Mohr, C.; Lienard, B.; Zondlo, J.; Oldham, N.; Clifton, I.; et al.

    2006-01-01

    Cellular and physiological responses to changes in dioxygen levels in metazoans are mediated via the posttranslational oxidation of hypoxia-inducible transcription factor (HIF). Hydroxylation of conserved prolyl residues in the HIF-{alpha} subunit, catalyzed by HIF prolyl-hydroxylases (PHDs), signals for its proteasomal degradation. The requirement of the PHDs for dioxygen links changes in dioxygen levels with the transcriptional regulation of the gene array that enables the cellular response to chronic hypoxia; the PHDs thus act as an oxygen-sensing component of the HIF system, and their inhibition mimics the hypoxic response. We describe crystal structures of the catalytic domain of human PHD2, an important prolyl-4-hydroxylase in the human hypoxic response in normal cells, in complex with Fe(II) and an inhibitor to 1.7 Angstroms resolution. PHD2 crystallizes as a homotrimer and contains a double-stranded {beta}-helix core fold common to the Fe(II) and 2-oxoglutarate-dependant dioxygenase family, the residues of which are well conserved in the three human PHD enzymes (PHD 1-3). The structure provides insights into the hypoxic response, helps to rationalize a clinically observed mutation leading to familial erythrocytosis, and will aid in the design of PHD selective inhibitors for the treatment of anemia and ischemic disease.

  18. Melatonin and the von Hippel-Lindau/HIF-1 oxygen sensing mechanism: A review.

    PubMed

    Vriend, Jerry; Reiter, Russel J

    2016-04-01

    There are numerous reports that melatonin inhibits the hypoxia-inducible factor, HIF-1α, and the HIF-1α-inducible gene, VEGF, both in vivo and in vitro. Through the inhibition of the HIF-1-VEGF pathway, melatonin reduces hypoxia-induced angiogenesis. Herein we discuss the interaction of melatonin with HIF-1α and HIF-1α-inducible genes in terms of what is currently known concerning the HIF-1α hypoxia response element (HIF-1α-HRE) pathway. The von Hippel-Lindau protein (VHL), also known as the VHL tumor suppressor, functions as part of a ubiquitin ligase complex which recognizes HIF-1α as a substrate. As such, VHL is part of the oxygen sensing mechanism of the cell. Under conditions of hypoxia, HIF-1α stimulates the transcription of numerous HIF-1α-induced genes, including EPO, VEGF, and PFKFB3; the latter is an enzyme which regulates glycolysis. Data from several studies show that ROS generated in mitochondria under conditions of hypoxia stimulate HIF-1α. Since melatonin acts as an antioxidant and reduces ROS, these data suggest that the antioxidant action of melatonin could account for reduced HIF-1, less VEGF, and reduced glycolysis in cancer cells (Warburg effect). A direct or indirect inhibitory action (via the reduction in ROS) of melatonin on proteasome activity would account for much of the published data.

  19. Room temperature alcohol sensing by oxygen vacancy controlled TiO{sub 2} nanotube array

    SciTech Connect

    Hazra, A.; Dutta, K.; Bhowmik, B.; Bhattacharyya, P.; Chattopadhyay, P. P.

    2014-08-25

    Oxygen vacancy (OV) controlled TiO{sub 2} nanotubes, having diameters of 50–70 nm and lengths of 200–250 nm, were synthesized by electrochemical anodization in the mixed electrolyte comprising NH{sub 4}F and ethylene glycol with selective H{sub 2}O content. The structural evolution of TiO{sub 2} nanoforms has been studied by field emission scanning electron microscopy. Variation in the formation of OVs with the variation of the structure of TiO{sub 2} nanoforms has been evaluated by photoluminescence and X-ray photoelectron spectroscopy. The sensor characteristics were correlated to the variation of the amount of induced OVs in the nanotubes. The efficient room temperature sensing achieved by the control of OVs of TiO{sub 2} nanotube array has paved the way for developing fast responding alcohol sensor with corresponding response magnitude of 60.2%, 45.3%, and 36.5% towards methanol, ethanol, and 2-propanol, respectively.

  20. Reactive oxygen species (ROS) and dimethylated sulphur compounds in coral explants under acute thermal stress.

    PubMed

    Gardner, Stephanie G; Raina, Jean-Baptiste; Ralph, Peter J; Petrou, Katherina

    2017-03-08

    Coral bleaching is intensifying with global climate change. While the causes for these catastrophic events are well understood, the cellular mechanism that triggers bleaching is not well established. Our understanding of coral bleaching processes is hindered by the lack of robust methods for studying interactions between host and symbiont at the single-cell level. Here we exposed coral explants to acute thermal stress and measured oxidative stress, more specifically, reactive oxygen species (ROS), in individual symbiont cells. Furthermore, we measured concentrations of dimethylsulphoniopropionate (DMSP) and dimethylsulphoxide (DMSO) to elucidate the role of these compounds in coral antioxidant function. This work demonstrates the application of coral explants for investigating coral physiology and biochemistry under thermal stress and delivers a new approach to study host-symbiont interactions at the microscale, allowing us to directly link intracellular ROS with DMSP and DMSO dynamics.

  1. Treatment of Adenoviral Acute Respiratory Distress Syndrome Using Cidofovir With Extracorporeal Membrane Oxygenation.

    PubMed

    Lee, Minhyeok; Kim, Seulgi; Kwon, Oh Jung; Kim, Ji Hye; Jeong, Inbeom; Son, Ji Woong; Na, Moon Jun; Yoon, Yoo Sang; Park, Hyun Woong; Kwon, Sun Jung

    2017-03-01

    Adenovirus infections are associated with respiratory (especially upper respiratory) infection and gastrointestinal disease and occur primarily in infants and children. Although rare in adults, severe lower respiratory adenovirus infections including pneumonia are reported in specific populations, such as military recruits and immunocompromised patients. Antiviral treatment is challenging due to limited clinical experience and lack of well-controlled randomized trials. Several previously reported cases of adenoviral pneumonia showed promising efficacy of cidofovir. However, few reports discussed the efficacy of cidofovir in acute respiratory distress syndrome (ARDS). We experienced 3 cases of adenoviral pneumonia associated with ARDS and treated with cidofovir and respiratory support, including extracorporeal membrane oxygenation (ECMO). All 3 patients showed a positive clinical response to cidofovir and survival at 28 days. Cidofovir with early ECMO therapy may be a therapeutic option in adenoviral ARDS. A literature review identified 15 cases of adenovirus pneumonia associated with ARDS.

  2. Oxygen-sensing mechanisms and the regulation of redox-responsive transcription factors in development and pathophysiology

    PubMed Central

    Haddad, John J

    2002-01-01

    How do organisms sense the amount of oxygen in the environment and respond appropriately when the level of oxygen decreases? Oxygen sensing and the molecular stratagems underlying the process have been the focus of an endless number of investigations trying to find an answer to the question: "What is the identity of the oxygen sensor?" Dynamic changes in pO2 constitute a potential signaling mechanism for the regulation of the expression and activation of reduction-oxidation (redox)-sensitive and oxygen-responsive transcription factors, apoptosis-signaling molecules and inflammatory cytokines. The transition from placental to lung-based respiration causes a relatively hyperoxic shift or oxidative stress, which the perinatal, developing lung experiences during birth. This variation in ΔpO2, in particular, differentially regulates the compartmentalization and functioning of the transcription factors hypoxia-inducible factor-1α (HIF-1α) and nuclear factor-κB (NF-κB). In addition, oxygen-evoked regulation of HIF-1α and NF-κB is closely coupled with the intracellular redox state, such that modulating redox equilibrium affects their responsiveness at the molecular level (expression/transactivation). The differential regulation of HIF-1α and NF-κB in vitro is paralleled by oxygen-sensitive and redox-dependent pathways governing the regulation of these factors during the transition from placental to lung-based respiration ex utero. The birth transition period in vivo and ex utero also regulates apoptosis signaling pathways in a redox-dependent manner, consistent with NF-κB being transcriptionally regulated in order to play an anti-apoptotic function. An association is established between oxidative stress conditions and the augmentation of an inflammatory state in pathophysiology, regulated by the oxygen- and redox-sensitive pleiotropic cytokines. PMID:12537605

  3. Which type of repetitive muscle contractions induces a greater acute impairment of position sense?

    PubMed

    Fortier, Sylvie; Basset, Fabien A; Billaut, François; Behm, David; Teasdale, Normand

    2010-04-01

    The objective of this study was to determine which type of repetitive muscle contractions induces a greater acute impairment of elbow position sense. Eleven male subjects participating in the study underwent (i) an exercise task (ET) consisting of 9 sets of 10 voluntary isometric, concentric, or eccentric contractions randomly performed on three separate sessions, and (ii) a pre- and post-exercise maximal voluntary isometric contraction (iMVC). Prior to and between sets of ET, a proprioception task (PT) consisting of matching the right arm to the left reference arm was performed at three different target angular positions (70 degrees , 110 degrees and 150 degrees). Each ET was immediately followed by 3 PT and 1 min rest. The statistical analysis revealed that post-exercise iMVCs were significantly decreased compared to pre-exercise iMVC in all conditions with a greater drop following the eccentric task. Despite this greater drop, position sense was significantly affected by the concentric exercise task. In addition, the spectral EMG signals significantly shifted towards lower frequencies from the initial values, regardless of exercise task. The results showed that concentric muscle contractions impaired position sense to a greater extent compared to isometric and eccentric contractions.

  4. Preservation of high glycolytic phenotype by establishing new acute lymphoblastic leukemia cell lines at physiologic oxygen concentration

    SciTech Connect

    Sheard, Michael A.; Ghent, Matthew V.; Cabral, Daniel J.; Lee, Joanne C.; Khankaldyyan, Vazgen; Ji, Lingyun; Wu, Samuel Q.; Kang, Min H.; and others

    2015-05-15

    Cancer cells typically exhibit increased glycolysis and decreased mitochondrial oxidative phosphorylation, and they continue to exhibit some elevation in glycolysis even under aerobic conditions. However, it is unclear whether cancer cell lines employ a high level of glycolysis comparable to that of the original cancers from which they were derived, even if their culture conditions are changed to physiologically relevant oxygen concentrations. From three childhood acute lymphoblastic leukemia (ALL) patients we established three new pairs of cell lines in both atmospheric (20%) and physiologic (bone marrow level, 5%) oxygen concentrations. Cell lines established in 20% oxygen exhibited lower proliferation, survival, expression of glycolysis genes, glucose consumption, and lactate production. Interestingly, the effects of oxygen concentration used during cell line initiation were only partially reversible when established cell cultures were switched from one oxygen concentration to another for eight weeks. These observations indicate that ALL cell lines established at atmospheric oxygen concentration can exhibit relatively low levels of glycolysis and these levels are semi-permanent, suggesting that physiologic oxygen concentrations may be needed from the time of cell line initiation to preserve the high level of glycolysis commonly exhibited by leukemias in vivo. - Highlights: • Establishing new ALL cell lines in 5% oxygen resulted in higher glycolytic expression and function. • Establishing new ALL cell lines in 5% oxygen resulted in higher proliferation and lower cell death. • The divergent metabolic phenotypes selected in 5% and 20% oxygen are semi-permanent.

  5. Combined administration of hyperbaric oxygen and hydroxocobalamin improves cerebral metabolism after acute cyanide poisoning in rats.

    PubMed

    Hansen, M B; Olsen, N V; Hyldegaard, O

    2013-11-01

    Hyperbaric oxygen therapy (HBOT) or intravenous hydroxocobalamin (OHCob) both abolish cyanide (CN)-induced surges in interstitial brain lactate and glucose concentrations. HBOT has been shown to induce a delayed increase in whole blood CN concentrations, whereas OHCob may act as an intravascular CN scavenger. Additionally, HBOT may prevent respiratory distress and restore blood pressure during CN intoxication, an effect not seen with OHCob administration. In this report, we evaluated the combined effects of HBOT and OHCob on interstitial lactate, glucose, and glycerol concentrations as well as lactate-to-pyruvate ratio in rat brain by means of microdialysis during acute CN poisoning. Anesthetized rats were allocated to three groups: 1) vehicle (1.2 ml isotonic NaCl intra-arterially); 2) potassium CN (5.4 mg/kg intra-arterially); 3) potassium CN, OHCob (100 mg/kg intra-arterially) and subsequent HBOT (284 kPa in 90 min). OHCob and HBOT significantly attenuated the acute surges in interstitial cerebral lactate, glucose, and glycerol concentrations compared with the intoxicated rats given no treatment. Furthermore, the combined treatment resulted in consistent low lactate, glucose, and glycerol concentrations, as well as in low lactate-to-pyruvate ratios compared with CN intoxicated controls. In rats receiving OHCob and HBOT, respiration improved and cyanosis disappeared, with subsequent stabilization of mean arterial blood pressure. The present findings indicate that a combined administration of OHCob and HBOT has a beneficial and persistent effect on the cerebral metabolism during CN intoxication.

  6. Reactive Oxygen Species Mediated Prostaglandin E2 Contributes to Acute Response of Epithelial Injury

    PubMed Central

    Hu, Yi-Ping; Zhang, Yi-Fan; Wang, Ying; Yu, Wei-Rong

    2017-01-01

    Reactive oxygen species (ROS) generated after tissue injury play a crucial role during wound healing through initiating acute inflammation, clarifying infection and dead tissue, and mediating various intracellular signal transduction. Prostaglandin E2 (PGE2) has been identified as one of the major factors responsible for inflammation and tissue repair. In this study, we tested our hypothesis that ROS produced by damaged human keratinocytes induces the synthesis of PGE2. In vitro epithelial wounding model was used to observe the production of ROS and secretion of PGE2 as well as the involved signal pathway. The mechanical injury caused the rapid production of ROS in in vitro cultured keratinocytes, which was significantly blocked by an inhibitor of nicotinamide adenine dinucleotide phosphate oxidase. The increased intracellular ROS caused by mechanical injury stimulates PGE2 production in a time-dependent manner via the activation of cyclooxygenase-2 (COX-2), which was stimulated by phosphorylation of extracellular signal-regulated protein kinase (ERK). These results indicate ROS-induced ERK activation leading to the activation of COX-2 and the synthesis of PGE2 in human keratinocytes responding to mechanical injury in the acute phase. PMID:28280524

  7. Biological oxygen sensing via two-photon absorption by an Ir(III) complex using a femtosecond fiber laser

    NASA Astrophysics Data System (ADS)

    Moritomo, Hiroki; Fujii, Akinari; Suzuki, Yasutaka; Yoshihara, Toshitada; Tobita, Seiji; Kawamata, Jun

    2016-09-01

    Near-infrared two-photon absorption of the phosphorescent Ir(III) complex (2,4-pentanedionato-κO 2,κO 4)bis[2-(6-phenanthridinyl-κN)benzo[b]thien-3-yl-κC]iridium (BTPHSA) was characterized. It exhibited a 800-1200 nm two-photon absorption band, and thus could be electronically excited by 1030-nm femtosecond Ti:sapphire and Yb-doped fiber lasers. By using BTPHSA, oxygen concentrations in human embryonic kidney 293 (HEK293) cells were imaged. These results demonstrate two-photon oxygen sensing of live tissues via easily operable excitation sources.

  8. PET imaging of cerebral perfusion and oxygen consumption in acute ischemic stroke: Relation to outcome

    SciTech Connect

    Marchal, G.; Serrati, C.; Rioux, P.; Petit-Taboue, M.C.; Viader, F.; Sayette, V. de la; Doze, F. le; Lonchon, P; Derlon, J.M.; Orgogozo, J.M.; Baron, J.C.

    1993-04-10

    The authors used positron emission tomography (PET) to assess the relation between combined imaging of cerebral blood flow and oxygen consumption 5-18 h after first middle cerebral artery (MCA) stroke and neurological outcome at 2 months. All 18 patients could be classified into three visually defined PET patterns of perfusion and oxygen consumption changes. Pattern 1 suggested extensive irreversible damage and was consistently associated with poor outcome. Pattern 2 suggested continuing ischemia and was associated with variable outcome. Pattern 3 with hyperperfusion and little or no metabolic alteration, was associated with excellent recovery, which suggests that early reperfusion is beneficial. This relation between PET and outcome was highly significant. The results suggest that within 5-18 h of stroke onset, PET is a good predictor of outcome in patterns 1 and 3, for which therapy seems limited. The absence of predictive value for pattern 2 suggests that it is due to a reversible ischemic state that is possibly amenable to therapy. These findings may have important implications for acute MCA stroke management and for patients' selection for therapeutic trials.

  9. Low Doses of Oxygen Ion Irradiation Cause Acute Damage to Hematopoietic Cells in Mice

    PubMed Central

    Wang, Yingying; Pathak, Rupak; Sridharan, Vijayalakshmi; Jones, Tamako; Mao, Xiao Wen; Nelson, Gregory; Boerma, Marjan; Hauer-Jensen, Martin; Zhou, Daohong; Shao, Lijian

    2016-01-01

    One of the major health risks to astronauts is radiation on long-duration space missions. Space radiation from sun and galactic cosmic rays consists primarily of 85% protons, 14% helium nuclei and 1% high-energy high-charge (HZE) particles, such as oxygen (16O), carbon, silicon, and iron ions. HZE particles exhibit dense linear tracks of ionization associated with clustered DNA damage and often high relative biological effectiveness (RBE). Therefore, new knowledge of risks from HZE particle exposures must be obtained. In the present study, we investigated the acute effects of low doses of 16O irradiation on the hematopoietic system. Specifically, we exposed C57BL/6J mice to 0.1, 0.25 and 1.0 Gy whole body 16O (600 MeV/n) irradiation and examined the effects on peripheral blood (PB) cells, and bone marrow (BM) hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) at two weeks after the exposure. The results showed that the numbers of white blood cells, lymphocytes, monocytes, neutrophils and platelets were significantly decreased in PB after exposure to 1.0 Gy, but not to 0.1 or 0.25 Gy. However, both the frequency and number of HPCs and HSCs were reduced in a radiation dose-dependent manner in comparison to un-irradiated controls. Furthermore, HPCs and HSCs from irradiated mice exhibited a significant reduction in clonogenic function determined by the colony-forming and cobblestone area-forming cell assays. These acute adverse effects of 16O irradiation on HSCs coincided with an increased production of reactive oxygen species (ROS), enhanced cell cycle entry of quiescent HSCs, and increased DNA damage. However, none of the 16O exposures induced apoptosis in HSCs. These data suggest that exposure to low doses of 16O irradiation induces acute BM injury in a dose-dependent manner primarily via increasing ROS production, cell cycling, and DNA damage in HSCs. This finding may aid in developing novel strategies in the protection of the hematopoietic

  10. Silicon-on-glass pore network micromodels with oxygen-sensing fluorophore films for chemical imaging and defined spatial structure.

    PubMed

    Grate, Jay W; Kelly, Ryan T; Suter, Jonathan; Anheier, Norm C

    2012-11-21

    Pore network microfluidic models were fabricated by a silicon-on-glass technique that provides the precision advantage of dry etched silicon while creating a structure that is transparent across all microfluidic channels and pores, and can be imaged from either side. A silicon layer is bonded to an underlying borosilicate glass substrate and thinned to the desired height of the microfluidic channels and pores. The silicon is then patterned and through-etched by deep reactive ion etching (DRIE), with the underlying glass serving as an etch stop. After bonding on a transparent glass cover plate, one obtains a micromodel in oxygen impermeable materials with water-wet surfaces where the microfluidic channels are transparent and structural elements such as the pillars creating the pore network are opaque. The advantageous features of this approach in a chemical imaging application are demonstrated by incorporating a Pt porphyrin fluorophore in a PDMS film serving as the oxygen-sensing layer and a bonding surface, or in a polystyrene film coated with a PDMS layer for bonding. The sensing of a dissolved oxygen gradient was demonstrated using fluorescence lifetime imaging, and it is shown that different matrix polymers lead to optimal use in different ranges of oxygen concentration. Imaging with the opaque pillars in between the observation direction and the continuous fluorophore film yields images that retain defined spatial structure in the sensor image.

  11. Silicon-on-glass pore network micromodels with oxygen-sensing fluorophore films for chemical imaging and defined spatial structure

    SciTech Connect

    Grate, Jay W.; Kelly, Ryan T.; Suter, Jonathan D.; Anheier, Norman C.

    2012-11-21

    Pore network microfluidic models were fabricated by a silicon-on-glass technique that provides the precision advantage of dry etched silicon while creating a structure that is transparent across all microfluidic channels and pores, and can be imaged from either side. A silicon layer is bonded to an underlying borosilicate glass substrate and thinned to the desired height of the microfluidic channels and pores. The silicon is then patterned and through-etched by deep reactive ion etching (DRIE), with the underlying glass serving as an etch stop. After bonding on a transparent glass cover plate, one obtains a micromodel in oxygen impermeable materials with water wet surfaces where the microfluidic channels are transparent and structural elements such as the pillars creating the pore network are opaque. The micromodel can be imaged from either side. The advantageous features of this approach in a chemical imaging application are demonstrated by incorporating a Pt porphyrin fluorophore in a PDMS film serving as the oxygen sensing layer and a bonding surface, or in a polystyrene film coated with a PDMS layer for bonding. The sensing of a dissolved oxygen gradient was demonstrated using fluorescence lifetime imaging, and it is shown that different matrix polymers lead to optimal use in different ranges dissolved oxygen concentration. Imaging with the opaque pillars in between the observation direction and the continuous fluorophore film yields images that retain spatial information in the sensor image.

  12. Exceptional Oxygen Sensing Properties of New Blue Light-Excitable Highly Luminescent Europium(III) and Gadolinium(III) Complexes

    PubMed Central

    Borisov, Sergey M.; Fischer, Roland; Saf, Robert; Klimant, Ingo

    2016-01-01

    New europium(III) and gadolinium(III) complexes bearing 8-hydroxyphenalenone antenna combine efficient absorption in the blue part of the spectrum and strong emission in polymers at room temperature. The Eu(III) complexes show characteristic red luminescence whereas the Gd(III) dyes are strongly phosphorescent. The luminescence quantum yields are about 20% for the Eu(III) complexes and 50% for the Gd(III) dyes. In contrast to most state-of-the-art Eu(III) complexes the new dyes are quenched very efficiently by molecular oxygen. The luminescence decay times of the Gd(III) complexes exceed 1 ms which ensures exceptional sensitivity even in polymers of moderate oxygen permeability. These sensors are particularly suitable for trace oxygen sensing and may be good substitutes for Pd(II) porphyrins. The photophysical and sensing properties can be tuned by varying the nature of the fourth ligand. The narrow-band emission of the Eu(III) allows efficient elimination of the background light and autofluorescence and is also very attractive for use e.g. in multi-analyte sensors. The highly photostable indicators incorporated in nanoparticles are promising for imaging applications. Due to the straightforward preparation and low cost of starting materials the new dyes represent a promising alternative to the state-of-the-art oxygen indicators particularly for such applications as e.g. food packaging. PMID:27158252

  13. DFT study of CO sensing mechanism on hexagonal WO3 (0 0 1) surface: The role of oxygen vacancy

    NASA Astrophysics Data System (ADS)

    Tian, FengHui; Zhao, Linghuan; Xue, Xu-Yan; Shen, Yaoyao; Jia, Xiangfeng; Chen, Shougang; Wang, Zonghua

    2014-08-01

    In this work, density functional theory (DFT) calculations have been used to study the adsorption of CO on the oxygen deficient hexagonal WO3 (h-WO3) (0 0 1) surface. Two different situations including the O- and WO-terminated h-WO3 (0 0 1) surfaces are considered. The influence of surface defect density is also concerned. Calculations proposed that the oxygen vacancy exert negative effects on the sensing ability of the h-WO3 material. Under relatively higher defect density, the presence of the oxygen vacancy on both of the O and WO-terminated (0 0 1) surfaces all decreases their sensitivity to CO gas to some extent, while they are still sensitive enough to detect CO gas with the charge transfers of 0.498 and 0.129 e, respectively. Whereas, under lower defect density, calculations indicated that the sensitivity of the material can be lowered largely.

  14. Determination of the Role of Oxygen in Suspected Acute Myocardial Infarction by Biomarkers

    ClinicalTrials.gov

    2017-03-02

    Acute Myocardial Infarction (AMI); Acute Coronary Syndrome (ACS); ST Elevation (STEMI) Myocardial Infarction; Ischemic Reperfusion Injury; Non-ST Elevation (NSTEMI) Myocardial Infarction; Angina, Unstable

  15. Ventilation and oxygen consumption during acute hypoxia in newborn mammals: a comparative analysis.

    PubMed

    Mortola, J P; Rezzonico, R; Lanthier, C

    1989-10-01

    We asked whether the lack of sustained hyperventilation during acute hypoxia, often reported to occur in the infant, is a common characteristic among newborn mammalian species, and to which extent inter-species differences may be accounted for by differences in metabolic responses. Ventilation (VE) and breathing pattern have been measured by flow-plethysmography or by the barometric method in normoxia and after 10 min of 10% O2 breathing in newborn mammals of 17 species over a 3 g to 20 kg range in body size. In 14 of these species oxygen consumption (VO2) has also been measured by a manometric technique or by calculation from the changes in chamber O2 pressure. VE and VO2 changed in proportion, among species, both in normoxia and hypoxia. In hypoxia, VE was higher, similar, or even lower than in normoxia, with some relation to the degree of maturity of the species at birth. In general, the small or absent VE responses to hypoxia resulted from small or no increase in tidal volume, while breathing frequency stayed elevated. The few departures from this pattern could be explained by interspecies differences in hypoxic sensitivity, since additional experiments in kittens and puppies indicated that, with more severe hypoxia, the pattern changed from rapid and shallow to deep and slow. In all cases, irrespective of the magnitude of the VE response, the VE/VO2 (and the mean inspiratory flow/VO2) increased during hypoxia, because the drop in VE, when present, was accompanied by an even larger drop in VO2. In fact, VO2 in hypoxia decreased in most species, although to variable degrees. Body temperature either did not change or decreased slightly, possibly indicating a trend toward a decrease of the set point of thermoregulation during hypoxia. In conclusion, the analysis gave further support to the concept that, during acute hypoxia, changes in metabolic rate play a paramount role in the ventilatory response of the newborn mammal.

  16. Repetitive hyperbaric oxygen treatment increases insulin sensitivity in diabetes patients with acute intracerebral hemorrhage

    PubMed Central

    Xu, Qian; Wei, Yi-ting; Fan, Shuang-bo; Wang, Liang; Zhou, Xiao-ping

    2017-01-01

    Aim The role of hyperbaric oxygen therapy (HBOT) in the treatment of acute ischemic stroke is controversial. This study aims to investigate whether the peripheral insulin sensitivity of type 2 diabetes patients suffering from intracerebral hemorrhage can be increased after HBOT. Methods Fifty-two type 2 diabetes participants were recruited after being diagnosed with intracerebral hemorrhage in our hospital. Insulin sensitivity was measured by the glucose infusion rate during a hyperinsulinemic euglycemic clamp (80 mU m−2 min−1) at baseline and 10 and 30 days after HBOT sessions. Serum insulin, fasting glucose, and hemoglobin A1C were measured in fasting serum at baseline and after HBOT sessions. In addition, early (∼10 days after onset) and late (1 month after onset) outcomes (National Institutes of Health Stroke Scale, NIHSS scores) and efficacy (changes of NIHSS scores) of HBOT were evaluated. Results In response to HBOT, the glucose infusion rate was increased by 37.8%±5.76% at 1 month after onset compared with baseline. Reduced serum insulin, fasting glucose, and hemoglobin A1C were observed after HBOT. Both early and late outcomes of the HBOT group were improved compared with baseline (P<0.001). In the control group, there was significant difference only in the late outcome (P<0.05). In the assessment of efficacy, there were statistically significant differences between the groups when comparing changes in NIHSS scores at 10 days and 1 month after onset (P<0.05). Conclusion Peripheral insulin sensitivity was increased following HBOT in type 2 diabetes patients with intracerebral hemorrhage. The HBOT used in this study may be effective for diabetes patients with acute stroke and is a safe and harmless adjunctive treatment. PMID:28228657

  17. Fluorescence-lifetime-based sensors: oxygen sensing and other biomedical applications

    NASA Astrophysics Data System (ADS)

    Randers-Eichhorn, Lisa; Bartlett, Roscoe A.; Sipior, Jeffrey; Frey, Douglas D.; Carter, Gary M.; Lakowicz, Joseph R.; Rao, Govind

    1996-05-01

    Murine hybridomas were cultivated in tissue culture flasks. Dissolved oxygen tensions in the gas and liquid phases during cell growth were measured non-invasively by an optical oxygen sensor. Readings were made with caps both cracked open and completely closed. During cell growth, gas phase oxygen concentrations remained near atmospheric levels, while the oxygen tension at the bottom of the flasks eventually reached zero. These results suggest that the widespread practice of cracking open tissue culture flask caps during cell growth with a view to supplying adequate oxygen to cells is ineffective and unnecessary. The mass transfer characteristics of the tissue culture flask indicate the dominant resistance to oxygen mass transfer to the cells was the liquid media. The mass transfer rates through the liquid layer under standard laboratory conditions were found to be greater than those predicted by diffusion alone, suggesting microscale mixing. Volumetric and specific oxygen consumption rates were calculated from the sensor data, and were comparable to published values. A recently developed single fiber optic oxygen sensor is described. This new sensor will provide oxygen concentrations at various levels in the tissue culture flasks, allowing more accurate modeling of oxygen diffusion.

  18. Determinants of maximal oxygen uptake in moderate acute hypoxia in endurance athletes.

    PubMed

    Mollard, Pascal; Woorons, Xavier; Letournel, Muriel; Lamberto, Christine; Favret, Fabrice; Pichon, Aurélien; Beaudry, Michèle; Richalet, Jean-Paul

    2007-08-01

    The factors determining maximal oxygen consumption were explored in eight endurance trained subjects (TS) and eight untrained subjects (US) exposed to moderate acute normobaric hypoxia. Subjects performed maximal incremental tests at sea level and simulated altitudes (1,000, 2,500, 4,500 m). Heart rate (HR), stroke volume (SV), cardiac output (.Q), arterialized oxygen saturation (Sa'O2), oxygen uptake (.VO2max), ventilation (.VE, expressed in normobaric conditions) were measured. At maximal exercise, ventilatory equivalent (.VE/.VO2max), O2 transport (.QaO2max) and O2 extraction (O2ERmax) were calculated. In TS, .Qmax remained unchanged despite a significant reduction in HRmax at 4,500 m. SVmax remained unchanged. .VEmax decreased in TS at 4,500 m, .VE/.VO2max was lower in TS and greater at 4,500 m vs. sea level in both groups. Sa'O2max decreased at and above 1,000 m in TS and 2,500 m in US, O2ERmax increased at 4,500 m in both groups. .QaO2max decreased with altitude and was greater in TS than US up to 2,500 m but not at 4,500 m. .VO2max decreased with altitude but the decrement (Delta.VO2max) was larger in TS at 4,500 m. In both groups Delta.VO2max in moderate hypoxia was correlated with Delta.QaO2max. Several differences between the two groups are probably responsible for the greater Delta.VO2max in TS at 4,500 m : (1) the relative hypoventilation in TS as shown by the decrement in .VEmax at 4,500 m (2) the greater.QaO2max decrement in TS due to a lower Sa'O2max and unchanged .Qmax 3) the smaller increase in O2ERmax in TS, insufficient to compensate the decrease in .QaO2max.

  19. Mechanical Ventilation during Extracorporeal Membrane Oxygenation in Patients with Acute Severe Respiratory Failure.

    PubMed

    Zhang, Zhongheng; Gu, Wan-Jie; Chen, Kun; Ni, Hongying

    2017-01-01

    Conventionally, a substantial number of patients with acute respiratory failure require mechanical ventilation (MV) to avert catastrophe of hypoxemia and hypercapnia. However, mechanical ventilation per se can cause lung injury, accelerating the disease progression. Extracorporeal membrane oxygenation (ECMO) provides an alternative to rescue patients with severe respiratory failure that conventional mechanical ventilation fails to maintain adequate gas exchange. The physiology behind ECMO and its interaction with MV were reviewed. Next, we discussed the timing of ECMO initiation based on the risks and benefits of ECMO. During the running of ECMO, the protective ventilation strategy can be employed without worrying about catastrophic hypoxemia and carbon dioxide retention. There is a large body of evidence showing that protective ventilation with low tidal volume, high positive end-expiratory pressure, and prone positioning can provide benefits on mortality outcome. More recently, there is an increasing popularity on the use of awake and spontaneous breathing for patients undergoing ECMO, which is thought to be beneficial in terms of rehabilitation.

  20. Mechanical Ventilation during Extracorporeal Membrane Oxygenation in Patients with Acute Severe Respiratory Failure

    PubMed Central

    Gu, Wan-Jie; Chen, Kun; Ni, Hongying

    2017-01-01

    Conventionally, a substantial number of patients with acute respiratory failure require mechanical ventilation (MV) to avert catastrophe of hypoxemia and hypercapnia. However, mechanical ventilation per se can cause lung injury, accelerating the disease progression. Extracorporeal membrane oxygenation (ECMO) provides an alternative to rescue patients with severe respiratory failure that conventional mechanical ventilation fails to maintain adequate gas exchange. The physiology behind ECMO and its interaction with MV were reviewed. Next, we discussed the timing of ECMO initiation based on the risks and benefits of ECMO. During the running of ECMO, the protective ventilation strategy can be employed without worrying about catastrophic hypoxemia and carbon dioxide retention. There is a large body of evidence showing that protective ventilation with low tidal volume, high positive end-expiratory pressure, and prone positioning can provide benefits on mortality outcome. More recently, there is an increasing popularity on the use of awake and spontaneous breathing for patients undergoing ECMO, which is thought to be beneficial in terms of rehabilitation. PMID:28127231

  1. The Complex Relationship of Extracorporeal Membrane Oxygenation and Acute Kidney Injury: Causation or Association?

    PubMed Central

    Kilburn, Daniel J.; Shekar, Kiran; Fraser, John F.

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is a modified cardiopulmonary bypass (CPB) circuit capable of providing prolonged cardiorespiratory support. Recent advancement in ECMO technology has resulted in increased utilisation and clinical application. It can be used as a bridge-to-recovery, bridge-to-bridge, bridge-to-transplant, or bridge-to-decision. ECMO can restitute physiology in critically ill patients, which may minimise the risk of progressive multiorgan dysfunction. Alternatively, iatrogenic complications of ECMO clearly contribute to worse outcomes. These factors affect the risk : benefit ratio of ECMO which ultimately influence commencement/timing of ECMO. The complex interplay of pre-ECMO, ECMO, and post-ECMO pathophysiological processes are responsible for the substantial increased incidence of ECMO-associated acute kidney injury (EAKI). The development of EAKI significantly contributes to morbidity and mortality; however, there is a lack of evidence defining a potential benefit or causative link between ECMO and AKI. This area warrants investigation as further research will delineate the mechanisms involved and subsequent strategies to minimise the risk of EAKI. This review summarizes the current literature of ECMO and AKI, considers the possible benefits and risks of ECMO on renal function, outlines the related pathophysiology, highlights relevant investigative tools, and ultimately suggests an approach for future research into this under investigated area of critical care. PMID:27006941

  2. Effect of oxygen plasma modification on refractive index sensing with micro-cavity in-line Mach-Zehnder interferometer

    NASA Astrophysics Data System (ADS)

    Debowska, Anna K.; Dominik, Magdalena; Koba, Marcin; Janik, Monika; Bock, Wojtek; Śmietana, Mateusz

    2016-12-01

    A micro-cavity in-line Mach-Zehnder interferometer (μIMZI) is an optical sensing structure fabricated in an optical fiber. Its design allows for refractive index sensing of liquid and gas in picoliter volumes, making it suitable for biochemical and medical sensing where measured material is often scarce. The fabricated structures show satisfactory levels of sensitivity, from about 400 nm/RIU in the near-water range of solutions (nD 1.336+/-0.003 RIU) to about 16 000 nm/RIU for solutions in approximate range from nD = 1.35 RIU to nD = 1.4 RIU. The structures were subjected to oxygen plasma, the process which was supposed to modify physical parameters of the structures, i.e., cavity surface wettability and roughness, and in consequence their sensitivity. As a result of the oxygen plasma modification we have observed a improved wettability of the structure surface, what makes it easier to introduce liquid into the cavity and simplifies the measurement process. In the case where the plasma processing is preceded by biological layer deposition, the bottom surface of the structure is smoothed and slightly deepened, causing a shift in the transmission spectrum and change in sensitivity.

  3. Enhancement of acute ethanol hepatotoxicity under conditions of low oxygen supply and ischemia/reperfusion. The role of oxygen radicals.

    PubMed

    Younes, M; Wagner, H; Strubelt, O

    1989-10-15

    Using isolated hemoglobin-free perfused rat livers we studied the effect of low oxygen supply on ethanol hepatotoxicity in two models. In the first model resembling low blood supply, perfusion rate was lowered from 60 to 10 ml/min after a 30 min-equilibration phase and kept low for 60 min. As a consequence, oxygen consumption fell from 1.76 +/- 0.15 mumol/min/g to 0.51 +/- 0.02 mumol/min/g. In the second model, total ischemia was accomplished by interruption of the perfusion for 30 min and was followed by reperfusion at a perfusion rate of 60 ml/min for a further 30 min. In this model, oxygen consumption returned immediately to normal values upon reperfusion. In both models, low oxygen supply had no toxic effects of its own on livers from fed rats. While ethanol (3 g/l) given under normoxic conditions led to a moderate hepatotoxicity, its application in both models of partial as well as total ischemia and reperfusion resulted in a marked liver damage as evidenced by a strong release of sorbitol dehydrogenase, glutamate-pyruvate-transaminase, lactate dehydrogenase and glutathione, as well as by an increase in hepatic calcium content. Inhibition of ethanol metabolism by 4-methylpyrazol prevented liver damage in both models indicating that metabolism of ethanol is a prerequisite for its toxicity to occur. Also, hepatotoxicity was inhibited partially by catalase and superoxide dismutase and nearly totally by deferrioxamine and allopurinol. Thus, reactive oxygen species which are produced during ethanol metabolism as well as under conditions of low oxygen supply are mediators of hepatic damage in both models employed.

  4. Mutual antagonism between hypoxia-inducible factors 1α and 2α regulates oxygen sensing and cardio-respiratory homeostasis.

    PubMed

    Yuan, Guoxiang; Peng, Ying-Jie; Reddy, Vaddi Damodara; Makarenko, Vladislav V; Nanduri, Jayasri; Khan, Shakil A; Garcia, Joseph A; Kumar, Ganesh K; Semenza, Gregg L; Prabhakar, Nanduri R

    2013-05-07

    Breathing and blood pressure are under constant homeostatic regulation to maintain optimal oxygen delivery to the tissues. Chemosensory reflexes initiated by the carotid body and catecholamine secretion from the adrenal medulla are the principal mechanisms for maintaining respiratory and cardiovascular homeostasis; however, the underlying molecular mechanisms are not known. Here, we report that balanced activity of hypoxia-inducible factor-1 (HIF-1) and HIF-2 is critical for oxygen sensing by the carotid body and adrenal medulla, and for their control of cardio-respiratory function. In Hif2α(+/-) mice, partial HIF-2α deficiency increased levels of HIF-1α and NADPH oxidase 2, leading to an oxidized intracellular redox state, exaggerated hypoxic sensitivity, and cardio-respiratory abnormalities, which were reversed by treatment with a HIF-1α inhibitor or a superoxide anion scavenger. Conversely, in Hif1α(+/-) mice, partial HIF-1α deficiency increased levels of HIF-2α and superoxide dismutase 2, leading to a reduced intracellular redox state, blunted oxygen sensing, and impaired carotid body and ventilatory responses to chronic hypoxia, which were corrected by treatment with a HIF-2α inhibitor. None of the abnormalities observed in Hif1α(+/-) mice or Hif2α(+/-) mice were observed in Hif1α(+/-);Hif2α(+/-) mice. These observations demonstrate that redox balance, which is determined by mutual antagonism between HIF-α isoforms, establishes the set point for hypoxic sensing by the carotid body and adrenal medulla, and is required for maintenance of cardio-respiratory homeostasis.

  5. Acute and chronic effects of parathion and 2,4 D on the oxygen consumption of Chasmagnathus granulata (Decapoda, Brachyura).

    PubMed

    Rodríguez, E M; Monserrat, J M

    1991-01-01

    The effect of two pesticides widely used in Argentina on the oxygen consumption of the estuarine crab Chasmagnathus granulata was studied. Constant pressure respirometers were employed to estimate the rate of oxygen consumption per weight unit of animals treated previously with each pesticide, both acute (96 h) and chronically (15 and 30 days). Crabs exposed to parathion -an organophosphorate insecticide that causes the inhibition of acetylcholinesterase- show an increase of oxygen consumption at 0.5 ppm under acute exposure, and at 10 ppb under a chronic one. On the other hand, crabs exposed to 2,4 D (an herbicide) did not show changes in their consumption after an acute exposure, but those exposed chronically did show an increase at low concentration (5 ppm) followed by a relative decrease at the highest concentration (50 ppm). The results obtained for parathion are in accordance with the abnormal cholinergic excitation that it may exert on crustacean nervous system. The effect of 2,4 D was consistent with its uncoupler action at respiratory chain level, at low concentrations, while a possible Krebs cycle enzymes inhibition might be occurring at higher concentrations of that pesticide, as in other crustacean species. The faster action of parathion, respect to 2,4 D, is explained by its neurotoxic nature.

  6. HIF-1α in epidermis: oxygen sensing, cutaneous angiogenesis, cancer, and non-cancer disorders.

    PubMed

    Rezvani, Hamid R; Ali, Nsrein; Nissen, Lars J; Harfouche, Ghida; de Verneuil, Hubert; Taïeb, Alain; Mazurier, Frédéric

    2011-09-01

    Besides lung, postnatal human epidermis is the only epithelium in direct contact with atmospheric oxygen. Skin epidermal oxygenation occurs mostly through atmospheric oxygen rather than tissue vasculature, resulting in a mildly hypoxic microenvironment that favors increased expression of hypoxia-inducible factor-1α (HIF-1α). Considering the wide spectrum of biological processes, such as angiogenesis, inflammation, bioenergetics, proliferation, motility, and apoptosis, that are regulated by this transcription factor, its high expression level in the epidermis might be important to HIF-1α in skin physiology and pathophysiology. Here, we review the role of HIF-1α in cutaneous angiogenesis, skin tumorigenesis, and several skin disorders.

  7. From critters to cancers: bridging comparative and clinical research on oxygen sensing, HIF signaling, and adaptations towards hypoxia.

    PubMed

    Hoogewijs, D; Terwilliger, N B; Webster, K A; Powell-Coffman, J A; Tokishita, S; Yamagata, H; Hankeln, T; Burmester, T; Rytkönen, K T; Nikinmaa, M; Abele, D; Heise, K; Lucassen, M; Fandrey, J; Maxwell, P H; Påhlman, S; Gorr, T A

    2007-10-01

    The objective of this symposium at the First International Congress of Respiratory Biology (ICRB) was to enhance communication between comparative biologists and cancer researchers working on O(2) sensing via the HIF pathway. Representatives from both camps came together on August 13-16, 2006, in Bonn, Germany, to discuss molecular adaptations that occur after cells have been challenged by a reduced (hypoxia) or completely absent (anoxia) supply of oxygen. This brief "critters-to-cancer" survey discusses current projects and new directions aimed at improving understanding of hypoxic signaling and developing therapeutic interventions.

  8. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2005-04-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. One of the critical materials issues is to demonstrate that the luminescent cluster immobilized in the sol-gel porous support can withstand high temperature. At the same time the sol-gel matrix must have a high permeability to oxygen. Using a potassium salt of the molybdenum clusters, K{sub 2}Mo{sub 6}Cl{sub 14}, we have established the conditions necessary for deposition of optical quality sol-gel films. From spectroscopic measurements of the film we have shown that the cluster luminescence is stable following heat cycling of 54 hours at 200 C. Quenching of a factor of 1.5X between pure nitrogen and 21% oxygen was observed from in-situ measurements of films heated directly at 200 C. An automated system for characterizing fiber optic oxygen sensors up to 220 C with a temporal resolution better than 10 s is under construction. We estimate a signal of 6 x 10{sup 8} photons/s after complete quenching in 21% oxygen. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  9. A New Combination Therapy in Severe Acute Pancreatitis—Hyperbaric Oxygen Plus 3-Aminobenzamide

    PubMed Central

    Inal, Volkan; Mas, Mehmet Refik; Isik, Ahmet Turan; Comert, Bilgin; Aydın, Sezai; Mas, Nukhet; Deveci, Mehmet Salih; Tasci, Ilker; Yamanel, Levent; Cinar, Esref; Unal, Mehmet Tahir

    2015-01-01

    Objectives This study was designed to evaluate effects of hyperbaric oxygen (HBO) plus 3-aminobenzamide (3-AB) cotreatment on tissue oxidative stress parameters (TOSp), tissue histopathology scores (THSc), and bacterial translocations (Bact-Trans) in an experimental model of severe acute pancreatitis (AP). Methods Seventy-five Sprague-Dawley rats were randomized into 5 groups. Group 1 received sham. Severe AP was induced by intraductal taurocholate infusion and then group 2 received saline, group 3 received 3-AB, group 4 received 3-AB plus HBO, and group 5 received HBO. 3-Aminobenzamide (10 mg/kg per day, once daily, intraperitoneal) and saline (1 mL/kg) were started right after the induction, whereas HBO (2,8 atm pressure, BID, 90 minutes each) was started at the sixth hour. The rats were euthanized at the 54th hour, and TOSp, THSc, and Bact-Trans were studied. Results In treatment groups 3 and 5, Bact-Trans (P < 0.05, P < 0.05), TOSp (P < 0.05, P < 0.05), and THSc (P < 0.001, P < 0.001) were significantly lower than controls. In addition to these findings, group 4 (cotreatment) showed the most significant effect on Bact-Trans and THSc (P < 0.001, P < 0.001) and also better in TOSp (P < 0.02). Conclusions Poly(ADP-ribose) polymerase inhibition by 3-AB and HBO treatment alone was effective in the course of severe AP, and favorable with cotreatment because of the improved cascades of inflammatory process by different aspects. PMID:25347462

  10. Restrictive transfusion practice during extracorporeal membrane oxygenation therapy for severe acute respiratory distress syndrome.

    PubMed

    Voelker, Maria T; Busch, Thilo; Bercker, Sven; Fichtner, Falk; Kaisers, Udo X; Laudi, Sven

    2015-04-01

    Recommendations concerning the management of hemoglobin levels and hematocrit in patients on extracorporeal membrane oxygenation (ECMO) still advise maintenance of a normal hematocrit. In contrast, current transfusion guidelines for critically ill patients support restrictive transfusion practice. We report on a series of patients receiving venovenous ECMO (vvECMO) for acute respiratory distress syndrome (ARDS) treated according to the restrictive transfusion regimen recommended for critically ill patients. We retrospectively analyzed 18 patients receiving vvECMO due to severe ARDS. Hemoglobin concentrations were kept between 7 and 9 g/dL with a transfusion trigger at 7 g/dL or when physiological transfusion triggers were apparent. We assessed baseline data, hospital mortality, time on ECMO, hemoglobin levels, hematocrit, quantities of packed red blood cells received, and lactate concentrations and compared survivors and nonsurvivors. The overall mortality of all patients on vvECMO was 38.9%. Mean hemoglobin concentration over all patients and ECMO days was 8.30 ± 0.51 g/dL, and hematocrit was 0.25 ± 0.01, with no difference between survivors and nonsurvivors. Mean numbers of given PRBCs showed a trend towards higher quantities in the group of nonsurvivors, but the difference was not significant (1.97 ± 1.47 vs. 0.96 ± 0.76 units; P = 0.07). Mean lactate clearance from the first to the third day was 45.4 ± 28.3%, with no significant difference between survivors and nonsurvivors (P = 0.19). In our cohort of patients treated with ECMO due to severe ARDS, the application of a restrictive transfusion protocol did not result in an increased mortality. Safety and feasibility of the application of a restrictive transfusion protocol in patients on ECMO must further be evaluated in randomized controlled trials.

  11. Predictors of Acute Renal Failure During Extracorporeal Membrane Oxygenation in Pediatric Patients After Cardiac Surgery.

    PubMed

    Lv, Lin; Long, Cun; Liu, Jinping; Hei, Feilong; Ji, Bingyang; Yu, Kun; Hu, Qiang; Hu, Jinxiao; Yuan, Yuan; Gao, Guodong

    2016-05-01

    Acute renal failure (ARF) is associated with increased mortality in pediatric extracorporeal membrane oxygenation (ECMO). The aim of this study was to identify predictors of ARF during ECMO in pediatric patients after cardiac surgery. A retrospective study analyzed 42 children (≤15 years) after cardiac surgery requiring venous-arterial ECMO between December 2008 and December 2014 at Fuwai Hospital. ARF was defined as ≥300% rise in serum creatinine (SCr) concentration from baseline or application of dialysis. Multivariate logistic regression was performed to identify the predictors of ARF during ECMO. A total of 42 children (age, interquartile range [IQR], 13.0 [7.2-29.8] months; weight, IQR, 8.5 [6.7-11.0] kg) after cardiac surgery requiring ECMO were included in this study. The total survival rate was 52.4%, and the incidence of ARF was 40.5%. As the result of univariate analysis, ECMO duration, cardiopulmonary resuscitation, maximum free hemoglobin (FHB) during ECMO, lactate level, and mean blood pressure before initiation of ECMO were entered in multiple logistic regression analysis. In multiple logistic regression analysis, FHB during ECMO (OR 1.136, 95% CI 1.023-1.261) and lactate level before initiation of ECMO (OR 1.602, 95% CI 1.025-2.502) were risk factors for ARF during ECMO after pediatric cardiac surgery. There was a linear correlation between maximum SCr and maximum FHB (Pearson's r = 0.535, P = 0.001). Maximum SCr during ECMO has also a linear correlation with lactate level before initiation of ECMO (Pearson's r = 0.342, P = 0.044). Increased FHB during ECMO and high lactate level before initiation of ECMO were risk factors for ARF during ECMO in pediatric patients after cardiac surgery.

  12. Lack of reactive oxygen species deteriorates blood pressure regulation in acute stress.

    PubMed

    Bernátová, I; Bališ, P; Goga, R; Behuliak, M; Zicha, J; Sekaj, I

    2016-10-24

    This study investigated the contribution of reactive oxygen species (ROS) to blood pressure regulation in conscious adult male Wistar rats exposed to acute stress. Role of ROS was investigated in rats with temporally impaired principal blood pressure regulation systems using ganglionic blocker pentolinium (P, 5 mg/kg), angiotensin converting enzyme inhibitor captopril (C, 10 mg/kg), nitric oxide synthase inhibitor L-NAME (L, 30 mg/kg) and superoxide dismutase mimeticum tempol (T, 25 mg/kg). Mean arterial pressure (MAP) was measured by the carotid artery catheter and inhibitors were administered intravenously. MAP was disturbed by a 3-s air jet, which increased MAP by 35.2+/-3.0 % vs. basal MAP after the first exposure. Air jet increased MAP in captopril- and tempol-treated rats similarly as observed in saline-treated rats. In pentolinium-treated rats stress significantly decreased MAP vs. pre-stress value. In L-NAME-treated rats stress failed to affect MAP significantly. Treatment of rats with P+L+C resulted in stress-induced MAP decrease by 17.3+/-1.3 % vs. pre-stress value and settling time (20.1+/-4.2 s). In P+L+C+T-treated rats stress led to maximal MAP decrease by 26.4+/-2.2 % (p<0.005 vs. P+L+C) and prolongation of settling time to 32.6+/-3.3 s (p<0.05 vs. P+L+C). Area under the MAP curve was significantly smaller in P+L+C-treated rats compared to P+L+C+T-treated ones (167+/-43 vs. 433+/-69 a.u., p<0.008). In conclusion, in rats with temporally impaired blood pressure regulation, the lack of ROS resulted in greater stress-induced MAP alterations and prolongation of time required to reach new post-stress steady state.

  13. Tubular cross talk in acute kidney injury: a story of sense and sensibility.

    PubMed

    El-Achkar, Tarek M; Dagher, Pierre C

    2015-06-15

    The mammalian kidney is an organ composed of numerous functional units or nephrons. Beyond the filtering glomerulus of each nephron, various tubular segments with distinct populations of epithelial cells sequentially span the kidney from cortex to medulla. The highly organized folding of the tubules results in a spatial distribution that allows intimate contact between various tubular subsegments. This unique arrangement can promote a newly recognized type of horizontal epithelial-to-epithelial cross talk. In this review, we discuss the importance of this tubular cross talk in shaping the response of the kidney to acute injury in a sense and sensibility model. We propose that injury-resistant tubules such as S1 proximal segments and thick ascending limbs (TAL) can act as "sensors" and thus modulate the responsiveness or "sensibility" of the S2-S3 proximal segments to injury. We also discuss new findings that highlight the importance of tubular cross talk in regulating homeostasis and inflammation not only in the kidney, but also systemically.

  14. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2006-05-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we described a particle-in-binder approach to immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the tips of optical fibers. Compared to previous methods, the particle-in-binder approach affords fibers with greatly improved mechanical properties. The response of the sensor to oxygen at 40, 70 and 100 C was measured in 2-21% gas phase oxygen. The normalized sensor signal is linear with molar oxygen concentration and fits the theoretical Stern-Volmer relationship. Although the sensitivity decreases with temperature, at 100 C the sensitivity is 160 [O{sub 2}]{sup -1}. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  15. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn; Po Zhang

    2006-06-30

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Our approach towards immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the far end of an optical fiber is to embed the cluster in a thermally cured sol-gel matrix particle. This particle-in-binder approach affords fibers with greatly improved mechanical properties, as compared to previous approaches. The sensor was characterized in 2-21% gas phase oxygen at 40, 70 and 100 C. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  16. Amphiphilic Fluorinated Polymer Nanoparticle Film Formation and Dissolved Oxygen Sensing Application

    NASA Astrophysics Data System (ADS)

    Gao, Yu; Zhu, Huie; Yamamoto, Shunsuke; Miyashita, Tokuji; Mitsuishi, Masaya

    2016-04-01

    Fluorinated polymer nanoparticle films were prepared by dissolving amphiphilic fluorinated polymer, poly (N-1H, 1H-pentadecafluorooctylmethacrylamide) (pC7F15MAA) in two miscible solvents (AK-225 and acetic acid). A superhydrophobic and porous film was obtained by dropcasting the solution on substrates. With higher ratios of AK-225 to acetic acid, pC7F15MAA was densified around acetic acid droplets, leading to the formation of pC7F15MAA nanoparticles. The condition of the nanoparticle film preparation was investigated by varying the mixing ratio or total concentration. A highly sensitive dissolved oxygen sensor system was successfully prepared utilizing a smart surface of superhydrophobic and porous pC7F15MAA nanoparticle film. The sensitivity showed I0/I40 = 126 in the range of dissolved oxygen concentration of 0 ~ 40 mg L-1. The oxygen sensitivity was compared with that of previous reports.

  17. The Stroke Oxygen Pilot Study: A Randomized Controlled Trial of the Effects of Routine Oxygen Supplementation Early after Acute Stroke—Effect on Key Outcomes at Six Months

    PubMed Central

    Ali, Khalid; Warusevitane, Anushka; Lally, Frank; Sim, Julius; Sills, Sheila; Pountain, Sarah; Nevatte, Tracy; Allen, Martin; Roffe, Christine

    2013-01-01

    Introduction Post-stroke hypoxia is common, and may adversely affect outcome. We have recently shown that oxygen supplementation may improve early neurological recovery. Here, we report the six-month outcomes of this pilot study. Methods Patients with a clinical diagnosis of acute stroke were randomized within 24 h of admission to oxygen supplementation at 2 or 3 L/min for 72 h or to control treatment (room air). Outcomes (see below) were assessed by postal questionnaire at 6 months. Analysis was by intention-to-treat, and statistical significance was set at p≤0.05. Results Out of 301 patients randomized two refused/withdrew consent and 289 (148 in the oxygen and 141 in the control group) were included in the analysis: males 44%, 51%; mean (SD) age 73 (12), 71 (12); median (IQR) National Institutes of Health Stroke Scale score 6 (3, 10), 5 (3, 10) for the two groups respectively. At six months 22 (15%) patients in the oxygen group and 20 (14%) in the control group had died; mean survival in both groups was 162 days (p = 0.99). Median (IQR) scores for the primary outcome, the modified Rankin Scale, were 3 (1, 5) and 3 (1, 4) for the oxygen and control groups respectively. The covariate-adjusted odds ratio was 1.04 (95% CI 0.67, 1.60), indicating that the odds of a lower (i.e. better) score were non-significantly higher in the oxygen group (p = 0.86). The mean differences in the ability to perform basic (Barthel Index) and extended activities of daily living (NEADL), and quality of life (EuroQol) were also non-significant. Conclusions None of the key outcomes differed at 6 months between the groups. Although not statistically significant and generally of small magnitude, the effects were predominantly in favour of the oxygen group; a larger trial, powered to show differences in longer-term functional outcomes, is now on-going. Trial Registration Controlled-Trials.com ISRCTN12362720; Eudract.ema.europa.eu 2004-001866-41 PMID:23755093

  18. Time-dependency of improvements in arterial oxygenation during partial liquid ventilation in experimental acute respiratory distress syndrome

    PubMed Central

    Max, Martin; Kuhlen, Ralf; Dembinski, Rolf; Rossaint, Rolf

    2000-01-01

    Background: The mechanisms by which partial liquid ventilation (PLV) can improve gas exchange in acute lung injury are still unclear. Therefore, we examined the time- and dose-dependency of the improvements in arterial oxygen tension (PaO2) due to PLV in eight pigs with experimental lung injury, in order to discriminate increases due to oxygen dissolved in perfluorocarbon before its intrapulmonary instillation from a persistent diffusion of the respiratory gas through the liquid column. Results: Application of four sequential doses of perfluorocarbon resulted in a dose-dependent increase in PaO2. Comparison of measurements 5 and 30 min after instillation of each dose revealed a time-dependent decrease in PaO2 for doses that approximated the functional residual capacity of the animals. Conclusion: Although oxygen dissolved in perfluorocarbon at the onset of PLV can cause a short-term improvement in arterial oxygenation, diffusion of oxygen through the liquid may not be sufficient to maintain the initially observed increase in PaO2. PMID:11056747

  19. Acute toxicity of lead on tolerance, oxygen consumption, ammonia-N excretion, and metal accumulation in Penaeus indicus postlarvae.

    PubMed

    Chinni, Satyavathi; Khan, Ritindra N; Yallapragada, Prabhakara Rao

    2002-02-01

    The estuaries and backwaters that are the potential breeding grounds of penaeid shrimps are subject to heavy metal pollution through industrial effluents and domestic sewage. In the present investigation, laboratory experiments were conducted to study the acute toxicity of lead on tolerance, oxygen consumption, ammonia-N excretion, and metal accumulation in Penaeus indicus postlarvae. Static bioassay tests were employed to determine tolerance limits. Oxygen consumption, ammonia-N excretion, and metal accumulation were determined in postlarvae by exposing them to different concentrations of lead for a period of 48 h. Oxygen consumption measurements were made by using a respiratory chamber equipped with an oxygen electrode and ammonia-N was determined with trione (dichloro-S-triamine 2,4,6(1H,3H,5H-trione)). Accumulation of metal was estimated by wet-ash method. The LC50 value for 96 h was 7.223 ppm and the regression equation Y=4.1638+0.9738X with correlation coefficient of 0.9613 was obtained by probit method. A decrease in oxygen consumption and ammonia-N excretion was observed in postlarvae with increasing concentration of lead. A concentration-dependent accumulation of metal was noticed in these postlarvae. Modifications in O:N ratios of postlarvae suggest that lead accumulation might have altered utilization patterns.

  20. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2005-01-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. One of the critical materials issues is to demonstrate that the luminescent cluster immobilized in the sol-gel porous support can withstand high temperature. At the same time the sol-gel matrix must have a high permeability to oxygen. Using a potassium salt of the molybdenum clusters, K{sub 2}Mo{sub 6}Cl{sub 14}, we have established the conditions necessary for deposition of optical quality sol-gel films. From spectroscopic measurements of the film we have shown that the cluster luminescence is stable following heat cycling of 1 hour at 250 C. Quenching of a factor of 4X between pure nitrogen and 21% oxygen was observed for films cured directly at 200 C. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  1. Multi-modal in vivo imaging of brain blood oxygenation, blood flow and neural calcium dynamics during acute seizures

    NASA Astrophysics Data System (ADS)

    Ringuette, Dene; Jeffrey, Melanie A.; Carlen, Peter L.; Levi, Ofer

    2016-03-01

    Dysfunction of the vascular endothelium has been implicated in the development of epilepsy. To better understand the relation between vascular function and seizure and provide a foundation for interpreting results from functional imaging in chronic disease models, we investigate the relationship between intracellular calcium dynamics and local cerebral blood flow and blood oxygen saturation during acute seizure-like events and pharmacological seizure rescue. To probe the relation between the aforementioned physiological markers in an acute model of epilepsy in rats, we integrated three different optical modalities together with electrophysiological recordings: Laser speckle contrast imaging (LSCI) was used to study changes in flow speeds, Intrinsic optical signal imaging (IOSI) was used to monitor changes in oxygenated, de-oxygenated, and total hemoglobin concentration, and Calcium-sensitive dye imaging was used to monitor intracellular calcium dynamics. We designed a dedicated cortical flow chamber to remove superficial blood and dye resulting from the injection procedure, which reduced spurious artifacts. The near infrared light used for IOSI and LSCI was delivered via a light pipe integrated with the flow chamber to minimize the effect of fluid surface movement on illumination stability. Calcium-sensitive dye was injected via a glass electrode used for recording the local field potential. Our system allowed us to observe and correlate increases in intracellular calcium, blood flow and blood volume during seizure-like events and provide a quantitative analysis of neurovascular coupling changes associated with seizure rescue via injection of an anti-convulsive agent.

  2. Human oxygen sensing may have origins in prokaryotic elongation factor Tu prolyl-hydroxylation

    PubMed Central

    Scotti, John S.; Leung, Ivanhoe K. H.; Ge, Wei; Bentley, Michael A.; Paps, Jordi; Kramer, Holger B.; Lee, Joongoo; Aik, WeiShen; Choi, Hwanho; Paulsen, Steinar M.; Bowman, Lesley A. H.; Loik, Nikita D.; Horita, Shoichiro; Ho, Chia-hua; Kershaw, Nadia J.; Tang, Christoph M.; Claridge, Timothy D. W.; Preston, Gail M.; McDonough, Michael A.; Schofield, Christopher J.

    2014-01-01

    The roles of 2-oxoglutarate (2OG)-dependent prolyl-hydroxylases in eukaryotes include collagen stabilization, hypoxia sensing, and translational regulation. The hypoxia-inducible factor (HIF) sensing system is conserved in animals, but not in other organisms. However, bioinformatics imply that 2OG-dependent prolyl-hydroxylases (PHDs) homologous to those acting as sensing components for the HIF system in animals occur in prokaryotes. We report cellular, biochemical, and crystallographic analyses revealing that Pseudomonas prolyl-hydroxylase domain containing protein (PPHD) contain a 2OG oxygenase related in structure and function to the animal PHDs. A Pseudomonas aeruginosa PPHD knockout mutant displays impaired growth in the presence of iron chelators and increased production of the virulence factor pyocyanin. We identify elongation factor Tu (EF-Tu) as a PPHD substrate, which undergoes prolyl-4-hydroxylation on its switch I loop. A crystal structure of PPHD reveals striking similarity to human PHD2 and a Chlamydomonas reinhardtii prolyl-4-hydroxylase. A crystal structure of PPHD complexed with intact EF-Tu reveals that major conformational changes occur in both PPHD and EF-Tu, including a >20-Å movement of the EF-Tu switch I loop. Comparison of the PPHD structures with those of HIF and collagen PHDs reveals conservation in substrate recognition despite diverse biological roles and origins. The observed changes will be useful in designing new types of 2OG oxygenase inhibitors based on various conformational states, rather than active site iron chelators, which make up most reported 2OG oxygenase inhibitors. Structurally informed phylogenetic analyses suggest that the role of prolyl-hydroxylation in human hypoxia sensing has ancient origins. PMID:25197067

  3. Human oxygen sensing may have origins in prokaryotic elongation factor Tu prolyl-hydroxylation.

    PubMed

    Scotti, John S; Leung, Ivanhoe K H; Ge, Wei; Bentley, Michael A; Paps, Jordi; Kramer, Holger B; Lee, Joongoo; Aik, WeiShen; Choi, Hwanho; Paulsen, Steinar M; Bowman, Lesley A H; Loik, Nikita D; Horita, Shoichiro; Ho, Chia-hua; Kershaw, Nadia J; Tang, Christoph M; Claridge, Timothy D W; Preston, Gail M; McDonough, Michael A; Schofield, Christopher J

    2014-09-16

    The roles of 2-oxoglutarate (2OG)-dependent prolyl-hydroxylases in eukaryotes include collagen stabilization, hypoxia sensing, and translational regulation. The hypoxia-inducible factor (HIF) sensing system is conserved in animals, but not in other organisms. However, bioinformatics imply that 2OG-dependent prolyl-hydroxylases (PHDs) homologous to those acting as sensing components for the HIF system in animals occur in prokaryotes. We report cellular, biochemical, and crystallographic analyses revealing that Pseudomonas prolyl-hydroxylase domain containing protein (PPHD) contain a 2OG oxygenase related in structure and function to the animal PHDs. A Pseudomonas aeruginosa PPHD knockout mutant displays impaired growth in the presence of iron chelators and increased production of the virulence factor pyocyanin. We identify elongation factor Tu (EF-Tu) as a PPHD substrate, which undergoes prolyl-4-hydroxylation on its switch I loop. A crystal structure of PPHD reveals striking similarity to human PHD2 and a Chlamydomonas reinhardtii prolyl-4-hydroxylase. A crystal structure of PPHD complexed with intact EF-Tu reveals that major conformational changes occur in both PPHD and EF-Tu, including a >20-Å movement of the EF-Tu switch I loop. Comparison of the PPHD structures with those of HIF and collagen PHDs reveals conservation in substrate recognition despite diverse biological roles and origins. The observed changes will be useful in designing new types of 2OG oxygenase inhibitors based on various conformational states, rather than active site iron chelators, which make up most reported 2OG oxygenase inhibitors. Structurally informed phylogenetic analyses suggest that the role of prolyl-hydroxylation in human hypoxia sensing has ancient origins.

  4. Low-cost microarray thin-film electrodes with ionic liquid gel-polymer electrolytes for miniaturised oxygen sensing.

    PubMed

    Lee, Junqiao; Silvester, Debbie S

    2016-06-21

    A robust, miniaturised electrochemical gas sensor for oxygen (O2) has been constructed using a commercially available Pt microarray thin-film electrode (MATFE) with a gellified electrolyte containing the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][NTf2]) and poly(methyl methacrylate) (PMMA) in a 50 : 50 mass ratio. Diffusion coefficients and solubilities for oxygen in mixtures of PMMA/RTIL at different PMMA doping concentrations (0-50% mass) were derived from potential step chronoamperometry (PSCA) on a Pt microdisk electrode. The MATFE was then used with both the neat RTIL and 50% (by mass) PMMA/RTIL gel, to study the analytical behavior over a wide concentration range (0.1 to 100 vol% O2). Cyclic voltammetry (CV) and long-term chronoamperometry (LTCA) techniques were employed and it was determined that the gentler CV technique is better at higher O2 concentrations (above 60 vol%), but LTCA is more reliable and accurate at lower concentrations (especially below 0.5% O2). In particular, there was much less potential shifting (from the unstable Pt quasi-reference electrode) evident in the 50% PMMA/RTIL gel than in the neat RTIL, making this a much more suitable electrolyte for long-term continuous oxygen monitoring. The mass production and low-cost of the electrode array, along with the minimal amounts of RTIL/PMMA required, make this a viable sensing device for oxygen detection on a bulk scale in a wide range of environmental conditions.

  5. EDTA-Decorated Nanostructured ZnO/CdS Thin Films for Oxygen Gas Sensing Applications

    NASA Astrophysics Data System (ADS)

    Arunraja, L.; Thirumoorthy, P.; Karthik, A.; Rajendran, V.; Edwinpaul, L.

    2016-08-01

    ZnO/CdS and ZnO/CdS-EDTA nanostructured thin films were prepared on a glass substrate using spin-coating and used for oxygen gas sensor applications. The structural properties of both ZnO/CdS and ZnO/CdS-EDTA nanostructured composites were comparatively characterized. The nanostructure thin film was found in a hexagonal structure with an average crystallite size reduced from 77 nm to 29 nm due to the influence of the EDTA. The optical absorption, photo luminescence, functional groups and surface morphology of the nanostructured thin films were comprehensively investigated. Oxygen was suitably tailored to verify the sensor response over a concentration range of 10-50 ppm at room temperature. Thus, the sensor studies reveal that the performance, response, and recovery time were enhanced in ZnO/CdS-EDTA nanostructured thin film compared with ZnO/CdS.

  6. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D. J. Osborn; Po Zhang

    2006-09-30

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Our approach towards immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the far end of an optical fiber is to embed the cluster in a thermally cured sol-gel matrix particle. Due to the improved mechanical properties of this approach high temperature sensor measurements were performed up to 100 C. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  7. The disulfide relay of the intermembrane space of mitochondria: an oxygen-sensing system?

    PubMed

    Bihlmaier, Karl; Mesecke, Nikola; Kloeppel, Christine; Herrmann, Johannes M

    2008-12-01

    The intermembrane space of mitochondria contains many proteins that lack classical mitochondrial targeting sequences. Instead, these proteins often show characteristic patterns of cysteine residues that are critical for their accumulation in the organelle. Import of these proteins is catalyzed by two essential components, Mia40 and Erv1. Mia40 is a protein in the intermembrane space that directly binds newly imported proteins via disulfide bonds. By reorganization of these bonds, intramolecular disulfide bonds are formed in the imported proteins, which are thereby released from Mia40 into the intermembrane space. Because folded proteins are unable to traverse the import pore of the outer membrane, this leads to a permanent location of these proteins within the mitochondria. During this reaction, Mia40 becomes reduced and needs to be re-oxidized to regain its activity. Oxidation of Mia40 is carried out by Erv1, a conserved flavine adenine dinucleotide (FAD)-binding sulfhydryl oxidase. Erv1 directly interacts with Mia40 and shuttles electrons from reduced Mia40 to oxidized cytochrome c, from whence they flow through cytochrome oxidase to molecular oxygen. The connection of the disulfide relay with the respiratory chain not only significantly increases the efficiency of the oxidase activity, but also prevents the formation of potentially deleterious hydrogen peroxide. The oxidative activity of Erv1 strongly depends on the oxygen concentration in mitochondria. Erv1, therefore, may function as a molecular switch that adapts mitochondrial activities to the oxygen levels in the cell.

  8. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2006-01-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we described a particle-in-binder approach to immobilizing the potassium salt of a molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the tips of optical fibers. Compared to previous methods, the particle-in-binder approach affords fibers with greatly improved mechanical properties. We have extensively characterized two fiber sensors at high temperature. We obtain quenching ratios between pure nitrogen and 21% oxygen as high as 3.9 x at 70 C. For the first sensor at 60 C we obtained a {+-} 1% variation in the quenching ratio over 6 cycles of measurement, and monitored the device performance over 23 days. We were able to operate the second sensor continuously for 14 hours at 70 C, and the sensor quenching ratio was stable to 5% over that time period. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  9. Severe Tumor Lysis Syndrome and Acute Pulmonary Edema Requiring Extracorporeal Membrane Oxygenation Following Initiation of Chemotherapy for Metastatic Alveolar Rhabdomyosarcoma.

    PubMed

    Sanford, Ethan; Wolbrink, Traci; Mack, Jennifer; Rowe, R Grant

    2016-05-01

    We present an 8-year-old male with metastatic alveolar rhabdomyosarcoma (ARMS) who developed precipitous cardiopulmonary collapse with severe tumor lysis syndrome (TLS) 48 hr after initiation of chemotherapy. Despite no detectable pulmonary metastases, acute hypoxemic respiratory failure developed, requiring extracorporeal membrane oxygenation (ECMO). Although TLS has been reported in disseminated ARMS, this singular case of life-threatening respiratory deterioration developing after initiation of chemotherapy presented unique therapeutic dilemmas. We review the clinical aspects of this case, including possible mechanisms of respiratory failure, and discuss the role of ECMO utilization in pediatric oncology.

  10. Acute respiratory distress syndrome (ARDS) treated successfully by veno-venous extracorporeal membrane oxygenation (ECMO) in a nearly drowned patient.

    PubMed

    Sonoo, Tomohiro; Ohshima, Kazuma; Kobayashi, Hiroaki; Asada, Toshifumi; Hiruma, Takahiro; Doi, Kento; Gunshin, Masataka; Murakawa, Tomohiro; Anraku, Masaki; Nakajima, Susumu; Nakajima, Jun; Yahagi, Naoki

    2014-09-01

    This report highlights about one acute respiratory distress syndrome (ARDS) case after near-drowning resuscitated using extracorporeal membrane oxygenation (ECMO). Few cases have been reported about ECMO use for near-drowning and in most of these cases, ECMO was initiated within the first week. However, in our report, we would like to emphasize that seemingly irreversible secondary worsening of ARDS after nearly drowned patient was successfully treated by ECMO use more than 1 week after near-drowning followed by discharge without home oxygen therapy, social support, or any complication. This is probably due to sufficient lung rest for ventilator-associated lung injury during ECMO use. Based on our case's clinical course, intensive care unit physicians must consider ECMO even in the late phase of worsened ARDS after near-drowning.

  11. Extracorporeal Membrane Oxygenation (ECMO) for Lung Injury in Severe Acute Respiratory Distress Syndrome (ARDS): Review of the Literature.

    PubMed

    Paolone, Summer

    2016-11-10

    Despite advances in mechanical ventilation, severe acute respiratory distress syndrome (ARDS) is associated with high morbidity and mortality rates ranging from 26% to 58%. Extracorporeal membrane oxygenation (ECMO) is a modified cardiopulmonary bypass circuit that serves as an artificial membrane lung and blood pump to provide gas exchange and systemic perfusion for patients when their own heart and lungs are unable to function adequately. ECMO is a complex network that provides oxygenation and ventilation and allows the lungs to rest and recover from respiratory failure while minimizing iatrogenic ventilator-induced lung injury. In critical care settings, ECMO is proven to improve survival rates and outcomes in patients with severe ARDS. This review defines severe ARDS; describes the ECMO circuit; and discusses recent research, optimal use of the ECMO circuit, limitations of therapy including potential complications, economic impact, and logistical factors; and discusses future research considerations.

  12. The acute antinociceptive effect of hyperbaric oxygen is not accompanied by an increase in markers of oxidative stress

    PubMed Central

    Liu, Shulin; Shirachi, Donald Y.; Quock, Raymond M.

    2014-01-01

    Aims Exposure to hyperbaric oxygen (HBO2) causes an antinociceptive response in mice. However, breathing oxygen (O2) at an elevated pressure can potentially cause oxygen toxicity. The aim of this study was to identify the determinants of HBO2 antinociception and the toxicity profile of HBO2. Main methods Male NIH Swiss mice were assessed for acute antinociceptive responsiveness under room air or 100% O2 at 1.0 or 3.5 atmospheres absolute (ATA), using the acetic acid-induced abdominal constriction test. For the oxygen toxicity test, mice were exposed to 3.5 ATA oxygen for 11 min, 60 min, 60 min daily for 2 days (120 min) or 60 min daily for 4 days (240 min), then assessed by analyzing the levels of two oxidative stress markers, MDA (malondialdehyde) and protein carbonyl in brain, spinal cord and lung. Key Findings Only the combination of 100% O2 and 3.5 ATA caused significant antinociception. The antinociceptive effect of 100% O2 was pressure-dependent up to 3.5 ATA. In the oxygen toxicity test, mice exposed to HBO2 for different time intervals had levels of brain, spinal cord and lung MDA and protein carbonyl that were comparable to that of control animals exposed to room air. Significance Treatment with 100% O2 evokes a pressure-dependent antinociceptive effect. Since there was no significant increase in levels of the oxidative stress markers in the tested tissues, it is concluded HBO2 at 3.5 ATA produces antinociception in the absence of oxidative stress in mice. PMID:24418003

  13. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III

    2004-10-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. High temperature measurements of the emission of clusters in sol gel films show that the luminescence intensity from the films follow a 1/T relationship from room temperature to 150 C, and then declines at a slower rate at higher temperatures. The large number of photons available at 230 C is consistent with simple low cost optics for fiber optic probes based on the emission from clusters in sol gel films.

  14. The polycystins are modulated by cellular oxygen-sensing pathways and regulate mitochondrial function

    PubMed Central

    Padovano, Valeria; Kuo, Ivana Y.; Stavola, Lindsey K.; Aerni, Hans R.; Flaherty, Benjamin J.; Chapin, Hannah C.; Ma, Ming; Somlo, Stefan; Boletta, Alessandra; Ehrlich, Barbara E.; Rinehart, Jesse; Caplan, Michael J.

    2017-01-01

    Autosomal dominant polycystic kidney disease is caused by mutations in the genes encoding polycystin-1 (PC1) and polycystin-2 (PC2), which form an ion channel complex that may mediate ciliary sensory processes and regulate endoplasmic reticulum (ER) Ca2+ release. Loss of PC1 expression profoundly alters cellular energy metabolism. The mechanisms that control the trafficking of PC1 and PC2, as well as their broader physiological roles, are poorly understood. We found that O2 levels regulate the subcellular localization and channel activity of the polycystin complex through its interaction with the O2-sensing prolyl hydroxylase domain containing protein EGLN3 (or PHD3), which hydroxylates PC1. Moreover, cells lacking PC1 expression use less O2 and show less mitochondrial Ca2+ uptake in response to bradykinin-induced ER Ca2+ release, indicating that PC1 can modulate mitochondrial function. These data suggest a novel role for the polycystins in sensing and responding to cellular O2 levels. PMID:27881662

  15. Primary endosymbiosis and the evolution of light and oxygen sensing in photosynthetic eukaryotes

    PubMed Central

    Rockwell, Nathan C.; Lagarias, J. Clark; Bhattacharya, Debashish

    2015-01-01

    The origin of the photosynthetic organelle in eukaryotes, the plastid, changed forever the evolutionary trajectory of life on our planet. Plastids are highly specialized compartments derived from a putative single cyanobacterial primary endosymbiosis that occurred in the common ancestor of the supergroup Archaeplastida that comprises the Viridiplantae (green algae and plants), red algae, and glaucophyte algae. These lineages include critical primary producers of freshwater and terrestrial ecosystems, progenitors of which provided plastids through secondary endosymbiosis to other algae such as diatoms and dinoflagellates that are critical to marine ecosystems. Despite its broad importance and the success of algal and plant lineages, the phagotrophic origin of the plastid imposed an interesting challenge on the predatory eukaryotic ancestor of the Archaeplastida. By engulfing an oxygenic photosynthetic cell, the host lineage imposed an oxidative stress upon itself in the presence of light. Adaptations to meet this challenge were thus likely to have occurred early on during the transition from a predatory phagotroph to an obligate phototroph (or mixotroph). Modern algae have recently been shown to employ linear tetrapyrroles (bilins) to respond to oxidative stress under high light. Here we explore the early events in plastid evolution and the possible ancient roles of bilins in responding to light and oxygen. PMID:25729749

  16. Carbon nanotubes-ionic liquid nanocomposites sensing platform for NADH oxidation and oxygen, glucose detection in blood.

    PubMed

    Bai, Lu; Wen, Dan; Yin, Jianyuan; Deng, Liu; Zhu, Chengzhou; Dong, Shaojun

    2012-03-15

    An excellent electrochemical sensing platform has been designed by combining the huge specific surface area of carbon nanotubes (CNTs) and the remarkable conductivity of ionic liquid (IL). IL can easily untangle CNTs bundles and disperse CNTs by itself under grinding condition due to the π-π interaction between CNTs and IL. The resulting nanocomposites showed an augmentation on the voltammetric and amperometric behaviors of electrocatalytic activity toward O(2) and NADH. Therefore, such an efficient platform was developed to fabricate mediator-free oxygen sensor and glucose biosensor based on glucose dehydrogenase (GDH). O(2) could be determined in the range of zero to one hundred percent of O(2) content with the detection limit of 126 μg L(-1) (S/N=3). The glucose biosensor which was constructed by entrapping GDH into chitosan on the nanocomposites modified glassy carbon electrode surface, exhibited good electrocatalytic oxidation toward glucose with a detection limit of 9 μM in the linear range of 0.02-1mM. We also applied the as-prepared sensors to detect oxygen and glucose in real blood samples and acquired satisfied results.

  17. n-Propyl gallate activates hypoxia-inducible factor 1 by modulating intracellular oxygen-sensing systems.

    PubMed

    Kimura, Motohide; Takabuchi, Satoshi; Tanaka, Tomoharu; Murata, Miyahiko; Nishi, Kenichiro; Oda, Seiko; Oda, Tomoyuki; Kanai, Michiyuki; Fukuda, Kazuhiko; Kizaka-Kondoh, Shinae; Adachi, Takehiko; Takabayashi, Arimichi; Semenza, Gregg L; Hirota, Kiichi

    2008-04-01

    HIF-1 (hypoxia-inducible factor 1) is a master regulator of cellular adaptive responses to hypoxia. The expression and transcriptional activity of the HIF-1alpha subunit is stringently controlled by intracellular oxygen tension through the action of prolyl and asparaginyl hydroxylases. In the present study we demonstrate that PG (n-propyl gallate) activates HIF-1 and expression of its downstream target genes under normoxic conditions in cultured cells and in mice. The stability and transcriptional activity of HIF-1alpha are increased by PG. PG treatment inhibits the interaction between HIF-1alpha and VHL (von Hippel-Lindau protein) and promotes the interaction between HIF-1alpha and p300, indicating that PG inhibits the activity of both prolyl and asparaginyl HIF-1alpha hydroxylases. We conclude that PG activates HIF-1 and enhances the resultant gene expression by directly affecting the intracellular oxygen sensing system in vitro and in vivo and that PG represents a lead compound for the development of a non-toxic activator of HIF-1.

  18. Singlet oxygen-induced photodegradation of the polymers and dyes in optical sensing materials and the effect of stabilizers on these processes.

    PubMed

    Enko, Barbara; Borisov, Sergey M; Regensburger, Johannes; Bäumler, Wolfgang; Gescheidt, Georg; Klimant, Ingo

    2013-09-12

    A comprehensive study of photodegradation processes in optical sensing materials caused by photosensitized singlet oxygen in different polymers is presented. The stabilities of the polymers are accessed in the oxygen consumption measurements performed with help of optical oxygen sensors. Polystyrene and poly(phenylsilesquioxane) are found to be the most stable among the polymers investigated, whereas poly(2,6-dimethyl-p-phenylene oxide) and particularly poly(methyl methacrylate) and their derivatives show the fastest oxygen consumption. The effect of the stabilizers (singlet oxygen quenchers) on the oxygen consumption rates, the photostability of the sensitizer, and the total photon emission (TPE) by singlet oxygen is studied. 1,4-Diazabicyclo[2.2.2]octane (DABCO) was found to significantly reduce both the TPE and the oxygen consumption rates, indicating its role as a physical quencher of singlet oxygen. The addition of DABCO also significantly improved the photostability of the sensitizer. The N-alkylated derivative of DABCO and DABCO covalently grafted to the polystyrene backbone are prepared in an attempt to overcome the volatility and water solubility of the quencher. These derivatives as well as other tertiary amines investigated were found to be inefficient as stabilizing agents, and some of them even negatively affected the oxygen consumption rates.

  19. Pulsed Dose Delivery of Oxygen in Mechanically Ventilated Pigs with Acute Lung Injury

    DTIC Science & Technology

    2013-03-01

    atropine (0.54 mg/kg). They were then intubated with 7.5 French endotracheal tubes. A surgical plane of anesthesia was maintained with isoflurane...patients often require intubation and mechanical ventilation with supplemental oxygen and positive end-expiratory pressure (PEEP). To date, the...circuit, directly at the endotracheal tube. We used the SeQual Eclipse II, which was selected for its oxygen generating capabilities, as it is capable

  20. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III

    2004-07-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Alkali salts of Mo{sub 6}Cl{sub 12} were synthesized and heated to 280 C for one hour in air. Optical measurements of the thermally treated material confirm the potential of the salts as lumophores in high temperature fiber optic sensors. In addition sol-gel films containing Mo{sub 6}Cl{sub 12} were dip coated on quartz substrates and heated at 200 C for one hour. Conditions were developed for successfully immobilizing monomeric complexes that are compatible with sol-gel processing.

  1. A Potassium-Dependent Oxygen Sensing Pathway Regulates Plant Root Hydraulics.

    PubMed

    Shahzad, Zaigham; Canut, Matthieu; Tournaire-Roux, Colette; Martinière, Alexandre; Boursiac, Yann; Loudet, Olivier; Maurel, Christophe

    2016-09-22

    Aerobic organisms survive low oxygen (O2) through activation of diverse molecular, metabolic, and physiological responses. In most plants, root water permeability (in other words, hydraulic conductivity, Lpr) is downregulated under O2 deficiency. Here, we used a quantitative genetics approach in Arabidopsis to clone Hydraulic Conductivity of Root 1 (HCR1), a Raf-like MAPKKK that negatively controls Lpr. HCR1 accumulates and is functional under combined O2 limitation and potassium (K(+)) sufficiency. HCR1 regulates Lpr and hypoxia responsive genes, through the control of RAP2.12, a key transcriptional regulator of the core anaerobic response. A substantial variation of HCR1 in regulating Lpr is observed at the Arabidopsis species level. Thus, by combinatorially integrating two soil signals, K(+) and O2 availability, HCR1 modulates the resilience of plants to multiple flooding scenarios.

  2. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2005-10-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we immobilized the potassium salt of a molybdenum cluster, K{sub 2}M{sub 6}Cl{sub 14}, in a sol-gel matrix and showed that the luminescence is stable after 54 hours at 200 C, but the quenching ratios were low and the films delaminated after thermal cycling due to densification of the matrix. Three new approaches to solve decreased quenching over time and delamination of films off fiber tips were investigated. In the first approach K{sub 2}Mo{sub 6}Cl{sub 14} embedded in cured sol-gel particles were incorporated into a TEOS based sol-gel. These gave enhanced quenching (6x), but delaminated. Our second approach was to use a commercial cyanoacrylate glue to immobilize the particles onto the tip of an optical fiber. This gave better adhesion and good quenching initially, but eventually the glue degraded upon heating. Our third approach was to use a 55% OtMOS/ TEOS sol-gel binder. Films based on this new sol-gel binder show high quenching ({approx}6x) and superior mechanical stability even after thermal cycling. Sensor measurements on an optical fiber containing K{sub 2}Mo{sub 6}Cl{sub 14} embedded in cured sol-gel particles were obtained from 100 to 25 C. The signal intensity in nitrogen was stable at 2.8 {+-} 0.2 nW, and the quenching ratio (ratio of signal in N{sub 2} vs. 21 % O{sub 2}) varied from 4.4 to 6.9X. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  3. Using Yttra-Stabilized Zirconium Oxide Ceramics to Sense pH and Oxygen in Hydrothermal and Geothermal Applications

    NASA Astrophysics Data System (ADS)

    Manna, M. F.; Grandstaff, D. E.; Ulmer, G. C.

    2002-05-01

    Zirconium-Oxide ceramics stabilized with ~8-wt% Yttrium-Oxide can be employed to sense pH in high temperature (>90oC) aqueous environments with an accuracy of 0.05 pH log units (Lvov et al., in press), and to sense the fugacity of oxygen (fO2) in low temperature (>230oC) gaseous environments with an accuracy of 0.2 (fO2) log units. The major components, in two commercially available yttria-stabilized ceramics are yttria ( ~8-wt%) and zirconia ( ~91-wt%) with minor amounts of Ti, Fe and U. The textural differences in the two ceramics produces significantly different emf vs. 10,000/T responses. Response error can be introduced by: the ionic contribution of the softening glass, the catalytic action of the Pt sensor components, and the presence of Ti and Fe in the ceramic, which has been shown to alter the oxygen diffusivity of the ceramic. (Merino et al., 1996) The first type of ceramic contains a 3-dimensionally-continuous Ca-Al-Si feldspathic glass that acts as a sintering aid during manufacturing. The glass, which has a higher ionic conductivity than the zirconia ceramic, reduces the bulk resistivity and induces an error over the temperature ranges representing the softening point of the glass. The glass also reduces durability of the ceramic. When the glass hydrates it produces zeolites, which grow primarily in the triple-grain-junctions of the ceramic. Thus mechanically weakening the ceramic generating electronic, ionic and mechanical stability problems. The second type of ceramic contains no grain boundary glass, but does contain discrete silicate phases (such as diopside, wollastonite, periclase, silica, etc.) in the triple-grain-junctions. Because there is no inter-granular glass, the type two ceramic does have a greater bulk resistivity compared with the type one ceramic. In a gas-sensing configuration, resistivity has been shown to affect the minimum temperature of sensor operation. A sensor with a higher bulk resistivity must reach a higher minimum

  4. Effect of nebulized budesonide on respiratory mechanics and oxygenation in acute lung injury/acute respiratory distress syndrome: Randomized controlled study

    PubMed Central

    Mohamed, Hatem Saber; Meguid, Mona Mohamed Abdel

    2017-01-01

    Background: We tested the hypothesis that nebulized budesonide would improve lung mechanics and oxygenation in patients with early acute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) during protective mechanical ventilation strategy without adversely affecting systemic hemodynamics. Methods: Patients with ALI/ARDS were included and assigned into two groups; budesonide group (30 cases) in whom 1 mg–2 ml budesonide suspension was nebulized through the endotracheal tube and control group (30 cases) in whom 2 ml saline (placebo) were nebulized instead of budesonide. This regimen was repeated every 12 h for three successive days alongside with constant ventilator settings in both groups. Hemodynamics, airway pressures, and PaO2/FiO2 were measured throughout the study period (72 h) with either nebulized budesonide or saline. Furthermore, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6) were analyzed serologically as markers of inflammation at pre- and post-nebulization sessions. Results: We found a significant difference between the two groups regarding PaO2/FiO2 (P = 0.023), peak (P = 0.021), and plateau (P = 0.032) airway pressures. Furthermore, TNF-α, IL-1β, and IL-6 were significantly reduced after budesonide nebulizations. No significant difference was found between the two groups regarding hemodynamic variables. Conclusion: Nebulized budesonide improved oxygenation, peak, and plateau airway pressures and significantly reduced inflammatory markers (TNF-α, IL-1β and IL-6) without affecting hemodynamics. Trial Registry: Australian New Zealand Clinical Trial Registry (ANZCTR) at the number: ACTRN12615000373572. PMID:28217046

  5. Effect of high-flow nasal cannula oxygen therapy in adults with acute hypoxemic respiratory failure: a meta-analysis of randomized controlled trials

    PubMed Central

    Ou, Xiaofeng; Hua, Yusi; Liu, Jin; Gong, Cansheng; Zhao, Wenling

    2017-01-01

    BACKGROUND: Conflicting recommendations exist on whether high-flow nasal cannula (HFNC) oxygen therapy should be administered to adult patients in critical care with acute hypoxemic respiratory failure. We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate its effect on intubation rates. METHODS: We searched electronic databases from inception to April 2016. We included RCTs that compared HFNC oxygen therapy with usual care (conventional oxygen therapy or noninvasive ventilation) in adults with acute hypoxemic respiratory failure. Because of the different methodologies and variation in clinical outcomes, we conducted 2 subgroup analyses according to oxygen therapy used and disease severity. We pooled data using random-effects models. The primary outcome was the proportion of patients who required endotracheal intubation. RESULTS: We included 6 RCTs (n = 1892). Compared with conventional oxygen therapy, HFNC oxygen therapy was associated with a lower intubation rate (risk ratio [RR] 0.60, 95% confidence interval [CI] 0.38 to 0.94; I2 = 49%). We found no significant difference in the rate between HFNC oxygen therapy and noninvasive ventilation (RR 0.86, 95% CI 0.68 to 1.09; I2 = 2%). In the subgroup analysis by disease severity, no significant differences were found in the intubation rate between HFNC oxygen therapy and either conventional oxygen therapy or noninvasive ventilation (interaction p = 0.3 and 0.4, respectively). INTERPRETATION: The intubation rate with HFNC oxygen therapy was lower than the rate with conventional oxygen therapy and similar to the rate with noninvasive ventilation among patients with acute hypoxemic respiratory failure. Larger, high-quality RCTs are needed to confirm these findings. PMID:28246239

  6. Acute effects of ferumoxytol on regulation of renal hemodynamics and oxygenation

    PubMed Central

    Cantow, Kathleen; Pohlmann, Andreas; Flemming, Bert; Ferrara, Fabienne; Waiczies, Sonia; Grosenick, Dirk; Niendorf, Thoralf; Seeliger, Erdmann

    2016-01-01

    The superparamagnetic iron oxide nanoparticle ferumoxytol is increasingly used as intravascular contrast agent in magnetic resonance imaging (MRI). This study details the impact of ferumoxytol on regulation of renal hemodynamics and oxygenation. In 10 anesthetized rats, a single intravenous injection of isotonic saline (used as volume control) was followed by three consecutive injections of ferumoxytol to achieve cumulative doses of 6, 10, and 41 mg Fe/kg body mass. Arterial blood pressure, renal blood flow, renal cortical and medullary perfusion and oxygen tension were continuously measured. Regulation of renal hemodynamics and oxygenation was characterized by dedicated interventions: brief periods of suprarenal aortic occlusion, hypoxia, and hyperoxia. None of the three doses of ferumoxytol resulted in significant changes in any of the measured parameters as compared to saline. Ferumoxytol did not significantly alter regulation of renal hemodynamics and oxygenation as studied by aortic occlusion and hypoxia. The only significant effect of ferumoxytol at the highest dose was a blunting of the hyperoxia-induced increase in arterial pressure. Taken together, ferumoxytol has only marginal effects on the regulation of renal hemodynamics and oxygenation. This makes ferumoxytol a prime candidate as contrast agent for renal MRI including the assessment of renal blood volume fraction. PMID:27436132

  7. Unconventional ratiometric-enhanced optical sensing of oxygen by mixed-phase TiO2

    NASA Astrophysics Data System (ADS)

    Lettieri, S.; Pallotti, D. K.; Gesuele, F.; Maddalena, P.

    2016-07-01

    We show that mixed-phase titanium dioxide (TiO2) can be effectively employed as an unconventional, inorganic, dual-emitting, and ratiometric optical sensor of O2. Simultaneous availability of rutile and anatase TiO2 photoluminescence (PL) and their peculiar "anti-correlated" PL responses to O2 allow using their ratio as a measurement parameter associated with the O2 concentration, leading to an experimental responsivity being by construction larger than the one obtainable for single-phase PL detection. A proof of this concept is given, showing a two-fold enhancement of the optical responsivity provided by the ratiometric approach. Besides the peculiar ratiometric-enhanced responsivity, other characteristics of mixed phase TiO2 can be envisaged as favorable for O2 optical probing, namely (a) low production costs, (b) absence of heterogeneous components, and (c) self-supporting properties. These characteristics encourage experimenting with its use for applications requiring high indicator quantities at a competitive price, possibly also tackling the need to develop supporting matrixes that carry the luminescent probes and avoiding issues related to the use of different components for ratiometric sensing.

  8. Role of distal arginine in early sensing intermediates in the heme domain of the oxygen sensor FixL.

    PubMed

    Jasaitis, Audrius; Hola, Klara; Bouzhir-Sima, Latifa; Lambry, Jean-Christophe; Balland, Veronique; Vos, Marten H; Liebl, Ursula

    2006-05-16

    FixL is a bacterial heme-based oxygen sensor, in which release of oxygen from the sensing PAS domain leads to activation of an associated kinase domain. Static structural studies have suggested an important role of the conserved residue arginine 220 in signal transmission at the level of the heme domain. To assess the role of this residue in the dynamics and properties of the initial intermediates in ligand release, we have investigated the effects of R220X (X = I, Q, E, H, or A) mutations in the FixLH heme domain on the dynamics and spectral properties of the heme upon photolysis of O(2), NO, and CO using femtosecond transient absorption spectroscopy. Comparison of transient spectra for CO and NO dissociation with steady-state spectra indicated less strain on the heme in the ligand dissociation species for all mutants compared to the wild type (WT). For CO and NO, the kinetics were similar to those of the wild type, with the exception of (1) a relatively low yield of picosecond NO rebinding to R220A, presumably related to the increase in the free volume of the heme pocket, and (2) substantial pH-dependent picosecond to nanosecond rebinding of CO to R220H, related to formation of a hydrogen bond between CO and histidine 220. Upon excitation of the complex bound with the physiological sensor ligand O(2), a 5-8 ps decay phase and a nondecaying (>4 ns) phase were observed for WT and all mutants. The strong distortion of the spectrum associated with the decay phase in WT is substantially diminished in all mutant proteins, indicating an R220-induced role of the heme in the primary intermediate in signal transmission. Furthermore, the yield of dissociated oxygen after this phase ( approximately 10% in WT) is increased in all mutants, up to almost unity in R220A, indicating a key role of R220 in caging the oxygen near the heme through hydrogen bonding. Molecular dynamics simulations corroborate these findings and suggest motions of O(2) and arginine 220 away from the heme

  9. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III

    2004-04-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. The luminescence of Mo{sub 6}Cl{sub 12} immobilized in a sol-gel matrix was measured as a function of heater temperature up to 200 C, in an inert environment. While the luminescence decreased with temperature, the integrated intensity at 200 C should be sufficient to enable detection of the luminescence in a fiber geometry. Previously we found that aging Mo{sub 6}Cl{sub 12} at temperatures above 250 C converts the canary yellow Mo{sub 6}Cl{sub 12} to a non-luminescent gray solid. Optical and thermal aging experiments show that the alkali metal salts of Mo{sub 6}Cl{sub 12} have higher thermal stabilities and remain luminescent after aging at 280 C.

  10. Oxygen sensing glucose biosensors based on alginate nano-micro systems

    NASA Astrophysics Data System (ADS)

    Chaudhari, Rashmi; Joshi, Abhijeet; Srivastava, Rohit

    2014-04-01

    Clinically glucose monitoring in diabetes management is done by point-measurement. However, an accurate, continuous glucose monitoring, and minimally invasive method is desirable. The research aims at developing fluorescence-mediated glucose detecting biosensors based on near-infrared radiation (NIR) oxygen sensitive dyes. Biosensors based on Glucose oxidase (GOx)-Rudpp loaded alginate microspheres (GRAM) and GOx-Platinum-octaethylporphyrin (PtOEP)-PLAalginate microsphere system (GPAM) were developed using air-driven atomization and characterized using optical microscopy, CLSM, fluorescence spectro-photometry etc. Biosensing studies were performed by exposing standard solutions of glucose. Uniform sized GRAM and GPAM with size 50+/-10μm were formed using atomization. CLSM imaging of biosensors suggests that Rudpp and PtOEP nanoparticles are uniformly distributed in alginate microspheres. The GRAM and GPAM showed a good regression constant of 0.974 and of 0.9648 over a range of 0-10 mM of glucose with a high sensitivity of 3.349%/mM (625 nm) and 2.38%/mM (645 nm) at 10 mM of glucose for GRAM and GPAM biosensor. GRAM and GPAM biosensors show great potential in development of an accurate and minimally invasive glucose biosensor. NIR dye based assays can aid sensitive, minimally-invasive and interference-free detection of glucose in diabetic patients.

  11. The effects of breathing a helium-oxygen gas mixture on maximal pulmonary ventilation and maximal oxygen consumption during exercise in acute moderate hypobaric hypoxia.

    PubMed

    Ogawa, Takeshi; Calbet, Jose A L; Honda, Yasushi; Fujii, Naoto; Nishiyasu, Takeshi

    2010-11-01

    To test the hypothesis that maximal exercise pulmonary ventilation (VE max) is a limiting factor affecting maximal oxygen uptake (VO2 max) in moderate hypobaric hypoxia (H), we examined the effect of breathing a helium-oxygen gas mixture (He-O(2); 20.9% O(2)), which would reduce air density and would be expected to increase VE max. Fourteen healthy young male subjects performed incremental treadmill running tests to exhaustion in normobaric normoxia (N; sea level) and in H (atmospheric pressure equivalent to 2,500 m above sea level). These exercise tests were carried out under three conditions [H with He-O(2), H with normal air and N] in random order. VO2 max and arterial oxy-hemoglobin saturation (SaO(2)) were, respectively, 15.2, 7.5 and 4.0% higher (all p < 0.05) with He-O(2) than with normal air (VE max, 171.9 ± 16.1 vs. 150.1 ± 16.9 L/min; VO2 max, 52.50 ± 9.13 vs. 48.72 ± 5.35 mL/kg/min; arterial oxyhemoglobin saturation (SaO(2)), 79 ± 3 vs. 76 ± 3%). There was a linear relationship between the increment in VE max and the increment in VO2 max in H (r = 0.77; p < 0.05). When subjects were divided into two groups based on their VO2 max, both groups showed increased VE max and SaO(2) in H with He-O(2), but VO2 max was increased only in the high VO2 max group. These findings suggest that in acute moderate hypobaric hypoxia, air-flow resistance can be a limiting factor affecting VE max; consequently, VO2 max is limited in part by VE max especially in subjects with high VO2 max.

  12. Pyruvate modifies metabolic flux and nutrient sensing during extracorporeal membrane oxygenation in an immature swine model

    SciTech Connect

    Ledee, Dolena R.; Kajimoto, Masaki; O'Kelly-Priddy, Colleen M.; Olson, Aaron; Isern, Nancy G.; Robillard Frayne, Isabelle; Des Rosiers, Christine; Portman, Michael A.

    2015-07-01

    Extracorporeal membrane oxygenation (ECMO) provides mechanical circulatory support for infants and children with postoperative cardiopulmonary failure. Nutritional support is mandatory during ECMO, although specific actions for substrates on the heart have not been delineated. Prior work shows that enhancing pyruvate oxidation promotes successful weaning from ECMO. Accordingly, we closely examined the role of prolonged systemic pyruvate supplementation in modifying metabolic parameters during the unique conditions of ventricular unloading provided by ECMO. Twelve male mixed breed Yorkshire piglets (age 30-49 days) received systemic infusion of either normal saline (Group C) or pyruvate (Group P) during ECMO for 8 hours. Over the final hour piglets received [2-13C] pyruvate, and [13C6]-L-leucine, as an indicator for oxidation and protein synthesis. A significant increase in lactate and pyruvate concentrations occurred, along with an increase in the absolute concentration of all measured CAC intermediates. Group P showed greater anaplerotic flux through pyruvate carboxylation although pyruvate oxidation relative to citrate synthase flux was similar to Group C. The groups demonstrated similar leucine fractional contributions to acetyl-CoA and fractional protein synthesis rates. Pyruvate also promoted an increase in the phosphorylation state of several nutrient sensitive enzymes, such as AMPK and ACC, and promoted O-GlcNAcylation through the hexosamine biosynthetic pathway (HBP). In conclusion, prolonged pyruvate supplementation during ECMO modified anaplerotic pyruvate flux and elicited changes in important nutrient and energy sensitive pathways, while preserving protein synthesis. Therefore, the observed results support the further study of nutritional supplementation and its downstream effects on cardiac adaptation during ventricular unloading.

  13. Pyruvate modifies metabolic flux and nutrient sensing during extracorporeal membrane oxygenation in an immature swine model

    PubMed Central

    Ledee, Dolena R.; Kajimoto, Masaki; O'Kelly Priddy, Colleen M.; Olson, Aaron K.; Isern, Nancy; Robillard-Frayne, Isabelle; Des Rosiers, Christine

    2015-01-01

    Extracorporeal membrane oxygenation (ECMO) provides mechanical circulatory support for infants and children with postoperative cardiopulmonary failure. Nutritional support is mandatory during ECMO although specific actions for substrates on the heart have not been delineated. Prior work shows that enhancing pyruvate oxidation promotes successful weaning from ECMO. Accordingly, we tested the hypothesis that prolonged systemic pyruvate supplementation activates pyruvate oxidation in an immature swine model in vivo. Twelve male mixed-breed Yorkshire piglets (age 30–49 days) received systemic infusion of either normal saline (group C) or pyruvate (group P) during the final 6 h of 8 h of ECMO. Over the final hour, piglets received [2-13C] pyruvate, as a reference substrate for oxidation, and [13C6]-l-leucine, as an indicator for amino acid oxidation and protein synthesis. A significant increase in lactate and pyruvate concentrations occurred, along with an increase in the absolute concentration of the citric acid cycle intermediates. An increase in anaplerotic flux through pyruvate carboxylation in group P occurred compared with no change in pyruvate oxidation. Additionally, pyruvate promoted an increase in the phosphorylation state of several nutrient-sensitive enzymes, like AMP-activated protein kinase and acetyl CoA carboxylase, suggesting activation for fatty acid oxidation. Pyruvate also promoted O-GlcNAcylation through the hexosamine biosynthetic pathway. In conclusion, although prolonged pyruvate supplementation did not alter pyruvate oxidation, it did elicit changes in nutrient- and energy-sensitive pathways. Therefore, the observed results support the further study of pyruvate and its downstream effect on cardiac function. PMID:25910802

  14. Sense and nonsense of high-dose cytarabine for acute myeloid leukemia.

    PubMed

    Löwenberg, Bob

    2013-01-03

    High-dose cytarabine applied during remission induction or as consolidation after attainment of a complete remission has become an established element in the treatment of adults with acute myeloid leukemia. Recent evidence has challenged the need for these exceptionally high-dose levels of cytarabine. In this review, we present a reappraisal of the usefulness of high-dose cytarabine for acute myeloid leukemia treatment.

  15. Reduced to oxidized glutathione ratios and oxygen sensing in calf and rabbit carotid body chemoreceptor cells

    PubMed Central

    Sanz-Alfayate, G; Obeso, A; Agapito, M T; González, C

    2001-01-01

    The aim of this work was to test the redox hypotheses of O2 chemoreception in the carotid body (CB). They postulate that hypoxia alters the levels of reactive oxygen species (ROS) and the ratio of reduced to oxidized glutathione (GSH/GSSG), causing modifications to the sulfhydryl groups/disulfide bonds of K+ channel proteins, which leads to the activation of chemoreceptor cells. We found that the GSH/GSSG ratio in normoxic calf CB (30.14 ± 4.67; n = 12) and hypoxic organs (33.03 ± 6.88; n = 10), and the absolute levels of total glutathione (0.71 ± 0.07 nmol (mg tissue)−1, normoxia vs. 0.76 ± 0.07 nmol (mg tissue)−1, hypoxia) were not statistically different. N-Acetylcysteine (2 mm; NAC), a precursor of glutathione and ROS scavenger, increased normoxic glutathione levels to 1.03 ± 0.06 nmol (mg tissue)−1 (P < 0.02) and GSH/GSSG ratios to 59.05 ± 5.05 (P < 0.001). NAC (20 μm–10 mm) did not activate or inhibit chemoreceptor cells as it did not alter the normoxic or the hypoxic release of 3H-catecholamines (3H-CAs) from rabbit and calf CBs whose CA deposits had been labelled by prior incubation with the natural CA precursor 3H-tyrosine. NAC (2 mm) was equally ineffective in altering the release of 3H-CAs induced by stimuli (high external K+ and ionomycin) that bypass the initial steps of the hypoxic cascade of activation of chemoreceptor cells, thereby excluding the possibility that the lack of effect of NAC on normoxic and hypoxic release of 3H-CAs results from a concomitant alteration of Ca2+ channels or of the exocytotic machinery. The present findings do not support the contention that O2 chemoreception in the CB is linked to variations in the GSH/GSSG quotient as the redox models propose. PMID:11711574

  16. Acute exposure of mercury chloride stimulates the tissue regeneration program and reactive oxygen species production in the Drosophila midgut.

    PubMed

    Chen, Zhi; Wu, Xiaochun; Luo, Hongjie; Zhao, Lingling; Ji, Xin; Qiao, Xianfeng; Jin, Yaping; Liu, Wei

    2016-01-01

    We used Drosophila as an animal model to study the digestive tract in response to the exposure of inorganic mercury (HgCl2). We found that after oral administration, mercury was mainly sequestered within the midgut. This resulted in increased cell death, which in turn stimulated the tissue regeneration program, including accelerated proliferation and differentiation of the intestinal stem cells (ISCs). We further demonstrated that these injuries correlate closely with the excessive production of the reactive oxygen species (ROS), as vitamin E, an antioxidant reagent, efficiently suppressed the HgCl2-induced phenotypes of midgut and improved the viability. We propose that the Drosophila midgut could serve as a suitable model to study the treatment of acute hydrargyrism on the digestive systems.

  17. [Recommendations for pediatric oxygen therapy in acute and chronic settings: needs assessment, implementation criteria, prescription practices and follow-up].

    PubMed

    Aubertin, G; Marguet, C; Delacourt, C; Houdouin, V; Leclainche, L; Lubrano, M; Marteletti, O; Pin, I; Pouessel, G; Rittié, J-L; Saulnier, J-P; Schweitzer, C; Stremler, N; Thumerelle, C; Toutain-Rigolet, A; Beydon, N

    2012-05-01

    Recommendations for acute and long-term oxygen therapy (needs assessment, implementation criteria, prescription practices, and follow-up) in children were produced by the Groupe de Recherche sur les Avancées en Pneumo-Pédiatrie (GRAPP) under the auspices of the French Paediatric Pulmonology and Allergology Society (SP2A). The Haute Autorité de Santé (HAS) methodology, based on the Formalized Consensus, was used. A first panel of experts analyzed the English and French literature to provide a second panel of experts with recommendations to validate. Only the recommendations are presented here, but the full text (arguments+recommendations) is available at the website of the French Paediatric Society: www.sfpediatrie.com.

  18. [Recommendations for pediatric oxygen therapy in acute and chronic settings: Needs assessment, implementation criteria, prescription practices and follow-up].

    PubMed

    Aubertin, G; Marguet, C; Delacourt, C; Houdouin, V; Leclainche, L; Lubrano, M; Marteletti, O; Pin, I; Pouessel, G; Rittié, J-L; Saulnier, J-P; Schweitzer, C; Stremler, N; Thumerelle, C; Toutain-Rigolet, A; Beydon, N

    2013-12-01

    Recommendations for acute and long-term oxygen therapy (needs assessment, implementation criteria, prescription practices, and follow-up) in children were produced by the Groupe de Recherche sur les Avancées en Pneumo-Pédiatrie (GRAPP) under the auspices of the French Paediatric Pulmonology and Allergology Society (SP2A). The Haute Autorité de Santé (HAS) methodology, based on the Formalized Consensus, was used. A first panel of experts analyzed the English and French literature to provide a second panel of experts with recommendations to validate. Only the recommendations are presented here, but the full text (arguments+recommendations) is available at the website of the French Paediatric Society: www.sfpediatrie.com.

  19. Acute EPOC response in women to circuit training and treadmill exercise of matched oxygen consumption.

    PubMed

    Braun, W A; Hawthorne, W E; Markofski, M M

    2005-08-01

    The purpose of the study was to evaluate the effects of circuit training (CT) and treadmill exercise performed at matched rates of oxygen consumption and exercise duration on elevated post-exercise oxygen consumption (EPOC) in untrained women, while controlling for the menstrual cycle. Eight, untrained females (31.3 +/- 9.1 years; 2.04 +/- 0.26 l min(-1) estimated VO2max; BMI=24.6+/-3.9 kg/m2) volunteered to participate in the study. Testing was performed during the early follicular phase for each subject to minimize hormonal variability between tests. Subjects performed two exercise sessions approximately 28 days apart. Resting, supine energy expenditure was measured for 30 min preceding exercise and for 1 h after completion of exercise. Respiratory gas exchange data were collected continuously during rest and exercise periods via indirect calorimetry. CT consisted of three sets of eight common resistance exercises. Pre-exercise and exercise oxygen consumption was not different between testing days (P>0.05). Thus, exercise conditions were appropriately matched. Analysis of EPOC data revealed that CT resulted in a significantly higher (p<0.05) oxygen uptake during the first 30 min of recovery (0.27 +/- 0.01 l min(-1) vs 0.23+/-0.01 l min(-1)); though, at 60 min, treatment differences were not present. Mean VO2 remained significantly higher (0.231 +/- 0.01 l min(-1)) than pre-exercise measures (0.193 +/- 0.01 l min(-1)) throughout the 60-min EPOC period (p<0.05). Heart rate, RPE, V(E) and RER were all significantly greater during CT (p<0.05). When exercise VO2 and exercise duration were matched, CT was associated with a greater metabolic disturbance and cost during the early phases of EPOC.

  20. Extracorporeal membrane oxygenation improves survival in a novel 24-hour pig model of severe acute respiratory distress syndrome

    PubMed Central

    Araos, Joaquín; Alegría, Leyla; García, Patricio; Damiani, Felipe; Tapia, Pablo; Soto, Dagoberto; Salomon, Tatiana; Rodriguez, Felipe; Amthauer, Macarena; Erranz, Benjamín; Castro, Gabriel; Carreño, Pamela; Medina, Tania; Retamal, Jaime; Cruces, Pablo; Bugedo, Guillermo; Bruhn, Alejandro

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is increasingly being used to treat severe acute respiratory distress syndrome (ARDS). However, there is limited clinical evidence about how to optimize the technique. Experimental research can provide an alternative to fill the actual knowledge gap. The purpose of the present study was to develop and validate an animal model of acute lung injury (ALI) which resembled severe ARDS, and which could be successfully supported with ECMO. Eighteen pigs were randomly allocated into three groups: sham, ALI, and ALI + ECMO. ALI was induced by a double-hit consisting in repeated saline lavage followed by a 2-hour period of injurious ventilation. All animals were followed up to 24 hours while being ventilated with conventional ventilation (tidal volume 10 ml/kg). The lung injury model resulted in severe hypoxemia, increased airway pressures, pulmonary hypertension, and altered alveolar membrane barrier function, as indicated by an increased protein concentration in bronchoalveolar fluid, and increased wet/dry lung weight ratio. Histologic examination revealed severe diffuse alveolar damage, characteristic of ARDS. Veno-venous ECMO was started at the end of lung injury induction with a flow > 60 ml/kg/min resulting in rapid reversal of hypoxemia and pulmonary hypertension. Mortality was 0, 66.6 and 16.6% in the SHAM, ALI and ALI + ECMO groups, respectively (p < 0.05). This is a novel clinically relevant animal model that can be used to optimize the approach to ECMO and foster translational research in extracorporeal lung support. PMID:27398166

  1. Extracorporeal membrane oxygenation improves survival in a novel 24-hour pig model of severe acute respiratory distress syndrome.

    PubMed

    Araos, Joaquín; Alegría, Leyla; García, Patricio; Damiani, Felipe; Tapia, Pablo; Soto, Dagoberto; Salomon, Tatiana; Rodriguez, Felipe; Amthauer, Macarena; Erranz, Benjamín; Castro, Gabriel; Carreño, Pamela; Medina, Tania; Retamal, Jaime; Cruces, Pablo; Bugedo, Guillermo; Bruhn, Alejandro

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is increasingly being used to treat severe acute respiratory distress syndrome (ARDS). However, there is limited clinical evidence about how to optimize the technique. Experimental research can provide an alternative to fill the actual knowledge gap. The purpose of the present study was to develop and validate an animal model of acute lung injury (ALI) which resembled severe ARDS, and which could be successfully supported with ECMO. Eighteen pigs were randomly allocated into three groups: sham, ALI, and ALI + ECMO. ALI was induced by a double-hit consisting in repeated saline lavage followed by a 2-hour period of injurious ventilation. All animals were followed up to 24 hours while being ventilated with conventional ventilation (tidal volume 10 ml/kg). The lung injury model resulted in severe hypoxemia, increased airway pressures, pulmonary hypertension, and altered alveolar membrane barrier function, as indicated by an increased protein concentration in bronchoalveolar fluid, and increased wet/dry lung weight ratio. Histologic examination revealed severe diffuse alveolar damage, characteristic of ARDS. Veno-venous ECMO was started at the end of lung injury induction with a flow > 60 ml/kg/min resulting in rapid reversal of hypoxemia and pulmonary hypertension. Mortality was 0, 66.6 and 16.6% in the SHAM, ALI and ALI + ECMO groups, respectively (p < 0.05). This is a novel clinically relevant animal model that can be used to optimize the approach to ECMO and foster translational research in extracorporeal lung support.

  2. Is acute static stretching able to reduce the time to exhaustion at power output corresponding to maximal oxygen uptake?

    PubMed

    Samogin Lopes, Felipe A; Menegon, Elton M; Franchini, Emerson; Tricoli, Valmor; de M Bertuzzi, Rômulo C

    2010-06-01

    This study analyzed the effect of an acute static stretching bout on the time to exhaustion (Tlim) at power output corresponding to VO2max. Eleven physically active male subjects (age 22.3+/-2.8 years, VO2max 2.7+/-0.5 L.min) completed an incremental cycle ergometer test, 2 muscle strength tests, and 2 maximal tests to exhaustion at power output corresponding to VO2max with and without a previous static stretching bout. The Tlim was not significantly affected by the static stretching (164+/-28 vs. 150+/-26 seconds with and without stretching, respectively, p=0.09), but the time to reach VO2max (118+/-22 vs. 102+/-25 seconds), blood-lactate accumulation immediately after exercise (10.7+/-2.9 vs. 8.0+/-1.7 mmol.L), and oxygen deficit (2.4+/-0.9 vs. 2.1+/-0.7 L) were significantly reduced (pacute static stretching bout did not reduce Tlim at power output corresponding to VO2max possibly by accelerating aerobic metabolism activation at the beginning of exercise. These results suggest that coaches and practitioners involved with aerobic dependent activities may use static stretching as part of their warm-up routines without fear of diminishing high-intensity aerobic exercise performance.

  3. Acute Myocardial Infarction Complicated by Cardiogenic Shock: An Algorithm-Based Extracorporeal Membrane Oxygenation Program Can Improve Clinical Outcomes.

    PubMed

    Unai, Shinya; Tanaka, Daizo; Ruggiero, Nicholas; Hirose, Hitoshi; Cavarocchi, Nicholas C

    2016-03-01

    Extracorporeal membrane oxygenation (ECMO) in our institution resulted in near total mortality prior to the establishment of an algorithm-based program in July 2010. We hypothesized that an algorithm-based ECMO program improves the outcome of patients with acute myocardial infarction complicated with cardiogenic shock. Between March 2003 and July 2013, 29 patients underwent emergent catheterization for acute myocardial infarction due to left main or proximal left anterior descending artery occlusion complicated with cardiogenic shock (defined as systolic blood pressure <90 mm Hg despite multiple inotropes, with or without intra-aortic balloon pump, lactic acidosis). Of 29 patients, 15 patients were treated before July 2010 (Group 1, old program), and 14 patients were treated after July 2010 (Group 2, new program). There were no significant differences in the baseline characteristics, including age, sex, coronary risk factors, and left ventricular ejection fraction between the two groups. Cardiopulmonary resuscitation prior to ECMO was performed in two cases (13%) in Group 1 and four cases (29%) in Group 2. ECMO support was performed in one case (6.7%) in Group 1 and six cases (43%) in Group 2. The 30-day survival of Group 1 versus Group 2 was 40 versus 79% (P = 0.03), and 1-year survival rate was 20 versus 56% (P = 0.01). The survival rate for patients who underwent ECMO was 0% in Group 1 versus 83% in Group 2 (P = 0.09). In Group 2, the mean duration on ECMO was 9.8 ± 5.9 days. Of the six patients who required ECMO in Group 2, 100% were successfully weaned off ECMO or were bridged to ventricular assist device implantation. Initiation of an algorithm-based ECMO program improved the outcomes in patients with acute myocardial infarction complicated by cardiogenic shock.

  4. Mitochondrial reactive oxygen species production by fish muscle mitochondria: Potential role in acute heat-induced oxidative stress.

    PubMed

    Banh, Sheena; Wiens, Lilian; Sotiri, Emianka; Treberg, Jason R

    2016-01-01

    Acute heat challenge is known to induce cell-level oxidative stress in fishes. Mitochondria are well known for the capacity to make reactive oxygen species (ROS) and as such are often implicated as a source of the oxidants associated with this thermally-induced oxidative stress. This implication is often asserted, despite little direct data for mitochondrial ROS metabolism in fishes. Here we characterize mitochondrial ROS metabolism in three Actinopterygian fish species at two levels, the capacity for superoxide/H2O2 production and the antioxidant thiol-reductase enzyme activities. We find that red muscle mitochondria from all three species have measurable ROS production and respond to different assay conditions consistent with what might be anticipated; assuming similar relative contributions from difference ROS producing sites as found in rat skeletal muscle mitochondria. Although there are species and assay specific exceptions, fish mitochondria may have a greater capacity to produce ROS than that found in the rat when either normalized to respiratory capacity or determined at a common assay temperature. The interspecific differences in ROS production are not correlated with thiol-based antioxidant reductase activities. Moreover, mimicking an acute in vivo heat stress by comparing the impact of increasing assay temperature on these processes in vitro, we find evidence supporting a preferential activation of mitochondrial H2O2 production relative to the increase in the capacity of reductase enzymes to supply electrons to the mitochondrial matrix peroxidases. This supports the contention that mitochondria may be, at least in part, responsible for the ROS that lead to oxidative stress in fish tissues exposed to acute heat challenge.

  5. Hyperbaric oxygen treatment of dogs has no effect on red cell deformability but causes an acute fluid shift.

    PubMed

    Martindale, V E; McKay, K

    1995-01-01

    Red blood cells respond to a number of perturbations, including hypoxia, with a reduction in deformability. Local hypoxia may become self-reinforcing, as hypoxic cells block capillaries preventing perfusion by oxygenated cells. Hyperbaric oxygen (HBO) is frequently used to treat conditions involving some degree of local hypoxia, but does it have a direct effect on deformability? To investigate this, 12 normal dogs received a 10 week "clinical" course of HBO: one 90 min treatment per weekday at 2.4 ATA (243 kPa), 100% O2. On Mondays and Fridays, a blood sample was drawn into EDTA, centrifuged, and the packed red blood cells resuspended in medium to a dilution of 2 x 10(6) to 5 x 10(6) cells/ml, and filtered under constant of 1.08 kPa through a precalibrated Nucleopore Hemafil Polycarbonate membrane. Filtrate was collected for one minute and weighed, and the red blood cell "incremental volume" calculated according to Engstrom (Engstrom and Ohlsson, Pediatric Res. 27:220-226, 1990). No significant change was seen in filtration rates, indicating that HBO itself neither improves nor impairs dog red blood cell deformability. Changes in other commonly measured blood parameters remained within clinical norms. An acute fluid shift out of red blood cells and into plasma was indicated.

  6. Oxygen-inducible glutamate oxaloacetate transaminase as protective switch transforming neurotoxic glutamate to metabolic fuel during acute ischemic stroke.

    PubMed

    Rink, Cameron; Gnyawali, Surya; Peterson, Laura; Khanna, Savita

    2011-05-15

    This work rests on our previous report (J Cereb Blood Flow Metab 30: 1275-1287, 2010) recognizing that glutamate (Glu) oxaloacetate transaminase (GOT) is induced when brain tissue hypoxia is corrected during acute ischemic stroke (AIS). GOT can metabolize Glu into tricarboxylic acid cycle intermediates and may therefore be useful to harness excess neurotoxic extracellular Glu during AIS as a metabolic substrate. We report that in cultured neural cells challenged with hypoglycemia, extracellular Glu can support cell survival as long as there is sufficient oxygenation. This effect is abrogated by GOT knockdown. In a rodent model of AIS, supplemental oxygen (100% O(2) inhaled) during ischemia significantly increased GOT expression and activity in the stroke-affected brain tissue and prevented loss of ATP. Biochemical analyses and in vivo magnetic resonance spectroscopy during stroke demonstrated that such elevated GOT decreased Glu levels at the stroke-affected site. In vivo lentiviral gene delivery of GOT minimized lesion volume, whereas GOT knockdown worsened stroke outcomes. Thus, brain tissue GOT emerges as a novel target in managing stroke outcomes. This work demonstrates that correction of hypoxia during AIS can help clear extracellular neurotoxic Glu by enabling utilization of this amino acid as a metabolic fuel to support survival of the hypoglycemic brain tissue. Strategies to mitigate extracellular Glu-mediated neurodegeneration via blocking receptor-mediated excitotoxicity have failed in clinical trials. We introduce the concept that under hypoglycemic conditions extracellular Glu can be transformed from a neurotoxin to a survival factor by GOT, provided there is sufficient oxygen to sustain cellular respiration.

  7. Use of two parallel oxygenators in a very large patient (2.76 m2) for an acute "A" dissecting aortic aneurysm repair.

    PubMed

    Lonský, Vladimir; Mand'ák, Jiri; Kubícek, Jaroslav; Volt, Martin; Procházka, Egon; Dominik, Jan

    2005-01-01

    The very large patient (weight 142 kg, height 197 cm, body surface 2.76 m2) was referred to acute operation with dissecting type A ascending aortic aneurysm. The calculated blood flow was 6.63 l/min. To anticipate potential difficulties with perfusion and oxygenation two oxygenators connected in parallel were incorporated into the circuit. Bentall procedure with ACB to the RCA was performed. The perfusion was uneventful. Bypass time was 259 minutes, cross clamp time 141 minutes, circulatory arrest 7 minutes. The highest oxygenators gas flow was 2.6 l/min with maximum FiO2 0.42. The use of two in parallel connected oxygenators is a very effective, easy and safe method in such extreme perfusions, offering to the perfusionist a great reserve of oxygenator output.

  8. On the mechanisms that limit oxygen uptake during exercise in acute and chronic hypoxia: role of muscle mass

    PubMed Central

    Calbet, José A L; Rådegran, Göran; Boushel, Robert; Saltin, Bengt

    2009-01-01

    Peak aerobic power in humans () is markedly affected by inspired O2 tension (). The question to be answered in this study is what factor plays a major role in the limitation of muscle peak in hypoxia: arterial O2 partial pressure () or O2 content ()? Thus, cardiac output (dye dilution with Cardio-green), leg blood flow (thermodilution), intra-arterial blood pressure and femoral arterial-to-venous differences in blood gases were determined in nine lowlanders studied during incremental exercise using a large (two-legged cycle ergometer exercise: Bike) and a small (one-legged knee extension exercise: Knee) muscle mass in normoxia, acute hypoxia (AH) () and after 9 weeks of residence at 5260 m (CH). Reducing the size of the active muscle mass blunted by 62% the effect of hypoxia on in AH and abolished completely the effect of hypoxia on after altitude acclimatization. Acclimatization improved Bike peak exercise from 34 ± 1 in AH to 45 ± 1 mmHg in CH (P < 0.05) and Knee from 38 ± 1 to 55 ± 2 mmHg (P < 0.05). Peak cardiac output and leg blood flow were reduced in hypoxia only during Bike. Acute hypoxia resulted in reduction of systemic O2 delivery (46 and 21%) and leg O2 delivery (47 and 26%) during Bike and Knee, respectively, almost matching the corresponding reduction in . Altitude acclimatization restored fully peak systemic and leg O2 delivery in CH (2.69 ± 0.27 and 1.28 ± 0.11 l min−1, respectively) to sea level values (2.65 ± 0.15 and 1.16 ± 0.11 l min−1, respectively) during Knee, but not during Bike. During Knee in CH, leg oxygen delivery was similar to normoxia and, therefore, also in spite of a of 55 mmHg. Reducing the size of the active muscle mass improves pulmonary gas exchange during hypoxic exercise, attenuates the Bohr effect on oxygen uploading at the lungs and preserves sea level convective O2 transport to the active muscles. Thus, the altitude-acclimatized human has potentially a similar exercising capacity as at sea level when the

  9. Phosphorescent Platinum(II) and Palladium(II) Complexes with Azatetrabenzoporphyrins—New Red Laser Diode-Compatible Indicators for Optical Oxygen Sensing

    PubMed Central

    2010-01-01

    A new class of oxygen indicators is described. Platinum(II) and palladium(II) complexes of azatetrabenzoporphyrins occupy an intermediate position between tetrabenzoporphyrins and phthalocyanines and combine features of both. The new dyes are excitable in the red part of the spectrum and possess strong room-temperature NIR phosphorescence. Other features include excellent spectral compatibility with the red laser diodes and 632.8 nm line of He−Ne laser, excellent photostability, and significantly shorter decay times than for the respective meso-tetraphenyltetrabenzoporphyrins. Applicability of the complexes for optical oxygen sensing is demonstrated. PMID:20186289

  10. Oxygen uptake and cardiovascular responses in control adults and acute myocardial infarction patients during bathing.

    PubMed

    Winslow, E H; Lane, L D; Gaffney, F A

    1985-01-01

    Physiological responses before, during, and after three types of baths were determined in 18 patients who were 5 to 17 days postinfarction and 22 control adults. In the patients, oxygen consumption (VO2) averaged 6, 7, and 7 ml/kg/min, peak heart rate 105, 108, and 112 beats per minute, and rate pressure product 115, 120, and 111 for basin, tub, and shower bathing, respectively. Oxygen consumption during bathing was less than 3 times resting levels. The patients had a significantly lower VO2 during bathing than the control subjects. The patients' peak heart rates were higher than anticipated for the level of exertion, and sometimes exceeded the target heart rates used in predischarge testing. Peak heart rate and occurrence of dysrhythmia did not differ significantly between the three types of baths. In the women patients, rate pressure product was significantly higher after tub bath than after basin bath or shower. The subjects had no cardiovascular symptoms during bathing, rated all three baths as light exertion, and disliked the basin bath. The data show that the physiologic costs of the three types of baths are similar, differences in responses to bathing seem more a function of subject variability than bath type, and many cardiac patients can take a tub bath or shower earlier in their hospitalization. However, more research is needed to predict patients likely to have an exaggerated response to bathing and to develop clear guidelines for bath method selection and progression.

  11. Monochloramine-sensitive amperometric microelectrode: optimization of gold, platinum, and carbon fiber sensing materials for removal of dissolved oxygen interference

    EPA Science Inventory

    Amperometric monochloramine detection using newly fabricated gold, platinum, and carbon-fiber microsensors was investigated to optimize sensor operation and eliminate oxygen interference. Gold and platinum microsensors exhibited no oxygen interference during monochloramine measu...

  12. The Aer protein and the serine chemoreceptor Tsr independently sense intracellular energy levels and transduce oxygen, redox, and energy signals for Escherichia coli behavior

    PubMed Central

    Rebbapragada, Anuradha; Johnson, Mark S.; Harding, Gordon P.; Zuccarelli, Anthony J.; Fletcher, Hansel M.; Zhulin, Igor B.; Taylor, Barry L.

    1997-01-01

    We identified a protein, Aer, as a signal transducer that senses intracellular energy levels rather than the external environment and that transduces signals for aerotaxis (taxis to oxygen) and other energy-dependent behavioral responses in Escherichia coli. Domains in Aer are similar to the signaling domain in chemotaxis receptors and the putative oxygen-sensing domain of some transcriptional activators. A putative FAD-binding site in the N-terminal domain of Aer shares a consensus sequence with the NifL, Bat, and Wc-1 signal-transducing proteins that regulate gene expression in response to redox changes, oxygen, and blue light, respectively. A double mutant deficient in aer and tsr, which codes for the serine chemoreceptor, was negative for aerotaxis, redox taxis, and glycerol taxis, each of which requires the proton motive force and/or electron transport system for signaling. We propose that Aer and Tsr sense the proton motive force or cellular redox state and thereby integrate diverse signals that guide E. coli to environments where maximal energy is available for growth. PMID:9380671

  13. Oxygen or cooling, to make a decision after acute ischemia stroke

    PubMed Central

    Liu, Wen-cao; Jin, Xin-chun

    2016-01-01

    The presence of a salvageable penumbra, a region of ischemic brain tissue with sufficient energy for short-term survival, has been widely agreed as the premise for thrombolytic therapy with tissue plasminogen activator (tPA), which remains the only United States Food and Drug Administration (FDA) approved treatment for acute ischemia stroke. However, the use of tPA has been profoundly constrained due to its narrow therapeutic time window and the increased risk of potentially deadly hemorrhagic transformation (HT). Blood brain barrier (BBB) damage within the thrombolytic time window is an indicator for tPA-induced HT and both normobaric hyperoxia (NBO) and hypothermia have been shown to protect the BBB from ischemia/reperfusion injury. Therefore, providing the O2 as soon as possible (NBO treatment), freezing the brain (hypothermia treatment) to slow down ischemia-induced BBB damage or their combined use may extend the time window for the treatment of tPA. In this review, we summarize the protective effects of NBO, hypothermia or their use combined with tPA on ischemia stroke, based on which, the combination of NBO and hypothermia may be an ideal early stroke treatment to preserve the ischemic penumbra. Given this, there is an urge for large randomized controlled trials to address the effect. PMID:28217292

  14. Fractal Dimension of EEG Activity Senses Neuronal Impairment in Acute Stroke

    PubMed Central

    Zappasodi, Filippo; Olejarczyk, Elzbieta; Marzetti, Laura; Assenza, Giovanni; Pizzella, Vittorio; Tecchio, Franca

    2014-01-01

    The brain is a self-organizing system which displays self-similarities at different spatial and temporal scales. Thus, the complexity of its dynamics, associated to efficient processing and functional advantages, is expected to be captured by a measure of its scale-free (fractal) properties. Under the hypothesis that the fractal dimension (FD) of the electroencephalographic signal (EEG) is optimally sensitive to the neuronal dysfunction secondary to a brain lesion, we tested the FD’s ability in assessing two key processes in acute stroke: the clinical impairment and the recovery prognosis. Resting EEG was collected in 36 patients 4–10 days after a unilateral ischemic stroke in the middle cerebral artery territory and 19 healthy controls. National Health Institute Stroke Scale (NIHss) was collected at T0 and 6 months later. Highuchi FD, its inter-hemispheric asymmetry (FDasy) and spectral band powers were calculated for EEG signals. FD was smaller in patients than in controls (1.447±0.092 vs 1.525±0.105) and its reduction was paired to a worse acute clinical status. FD decrease was associated to alpha increase and beta decrease of oscillatory activity power. Larger FDasy in acute phase was paired to a worse clinical recovery at six months. FD in our patients captured the loss of complexity reflecting the global system dysfunction resulting from the structural damage. This decrease seems to reveal the intimate nature of structure-function unity, where the regional neural multi-scale self-similar activity is impaired by the anatomical lesion. This picture is coherent with neuronal activity complexity decrease paired to a reduced repertoire of functional abilities. FDasy result highlights the functional relevance of the balance between homologous brain structures’ activities in stroke recovery. PMID:24967904

  15. Fractal dimension of EEG activity senses neuronal impairment in acute stroke.

    PubMed

    Zappasodi, Filippo; Olejarczyk, Elzbieta; Marzetti, Laura; Assenza, Giovanni; Pizzella, Vittorio; Tecchio, Franca

    2014-01-01

    The brain is a self-organizing system which displays self-similarities at different spatial and temporal scales. Thus, the complexity of its dynamics, associated to efficient processing and functional advantages, is expected to be captured by a measure of its scale-free (fractal) properties. Under the hypothesis that the fractal dimension (FD) of the electroencephalographic signal (EEG) is optimally sensitive to the neuronal dysfunction secondary to a brain lesion, we tested the FD's ability in assessing two key processes in acute stroke: the clinical impairment and the recovery prognosis. Resting EEG was collected in 36 patients 4-10 days after a unilateral ischemic stroke in the middle cerebral artery territory and 19 healthy controls. National Health Institute Stroke Scale (NIHss) was collected at T0 and 6 months later. Highuchi FD, its inter-hemispheric asymmetry (FDasy) and spectral band powers were calculated for EEG signals. FD was smaller in patients than in controls (1.447±0.092 vs 1.525±0.105) and its reduction was paired to a worse acute clinical status. FD decrease was associated to alpha increase and beta decrease of oscillatory activity power. Larger FDasy in acute phase was paired to a worse clinical recovery at six months. FD in our patients captured the loss of complexity reflecting the global system dysfunction resulting from the structural damage. This decrease seems to reveal the intimate nature of structure-function unity, where the regional neural multi-scale self-similar activity is impaired by the anatomical lesion. This picture is coherent with neuronal activity complexity decrease paired to a reduced repertoire of functional abilities. FDasy result highlights the functional relevance of the balance between homologous brain structures' activities in stroke recovery.

  16. Oxygen Sensing via the Ethylene Response Transcription Factor RAP2.12 Affects Plant Metabolism and Performance under Both Normoxia and Hypoxia1[OPEN

    PubMed Central

    Paul, Melanie Verena; Iyer, Srignanakshi; Lehmann, Martin

    2016-01-01

    Subgroup-VII-ethylene-response-factor (ERF-VII) transcription factors are involved in the regulation of hypoxic gene expression and regulated by proteasome-mediated proteolysis via the oxygen-dependent branch of the N-end-rule pathway. While research into ERF-VII mainly focused on their role to regulate anoxic gene expression, little is known on the impact of this oxygen-sensing system in regulating plant metabolism and growth. By comparing Arabidopsis (Arabidopsis thaliana) plants overexpressing N-end-rule-sensitive and insensitive forms of the ERF-VII-factor RAP2.12, we provide evidence that oxygen-dependent RAP2.12 stability regulates central metabolic processes to sustain growth, development, and anoxic resistance of plants. (1) Under normoxia, overexpression of N-end-rule-insensitive Δ13RAP2.12 led to increased activities of fermentative enzymes and increased accumulation of fermentation products, which were accompanied by decreased adenylate energy states and starch levels, and impaired plant growth and development, indicating a role of oxygen-regulated RAP2.12 degradation to prevent aerobic fermentation. (2) In Δ13RAP2.12-overexpressing plants, decreased carbohydrate reserves also led to a decrease in anoxic resistance, which was prevented by external Suc supply. (3) Overexpression of Δ13RAP2.12 led to decreased respiration rates, changes in the levels of tricarboxylic acid cycle intermediates, and accumulation of a large number of amino acids, including Ala and γ-amino butyric acid, indicating a role of oxygen-regulated RAP2.12 abundance in controlling the flux-modus of the tricarboxylic acid cycle. (4) The increase in amino acids was accompanied by increased levels of immune-regulatory metabolites. These results show that oxygen-sensing, mediating RAP2.12 degradation is indispensable to optimize metabolic performance, plant growth, and development under both normoxic and hypoxic conditions. PMID:27372243

  17. The acute effects of nicotine, tobacco smoke and carbon monoxide on myocardial oxygen tension in the anaesthetized cat

    PubMed Central

    Rink, Richard D.

    1978-01-01

    1 The acute effects of nicotine, tobacco smoke, and carbon monoxide on myocardial oxygen tension (MPo2) were estimated amperometrically in 33 anaesthetized open-chest cats with a glass-insulated 25 μm platinum cathode within a 22-gauge needle implanted in the left ventricular wall. 2 MPo2 was 1.6-60 mmHg (mean 23.5 mmHg) when arterial Po2 was >80 mmHg. Sequential intravenous infusions of nicotine (2-3 μg/kg every 45 s) or intracheal puffs (3-5 ml) of tobacco smoke commonly produced transitory increases (25-35 mmHg) of arterial pressure and 4-6 mmHg increments of MPo2. Intratracheal puffs (5 ml) of 5% carbon monoxide sufficient to increase carboxyhaemoglobin from 0.8 to 1.5% to 4-7% had no effect on arterial Po2 or blood pressure but typically decreased MPo2 by approximately 1-4 mmHg. Augmentation of MPo2 often succeeded carbon monoxide administration. 3 Arterial hypoxia (arterial Po2 < 60 mmHg) reduced mean MPo2 to 14.4 mmHg but anoxic levels were not observed. Pressor responses to nicotine and tobacco smoke were accompanied by small increases (usually 1-3 mmHg) of MPo2. Puffs of 5% carbon monoxide had less effect than during normoxia. Locations of low MPo2 (<10 mmHg) were unaffected as carboxyhaemoglobin was raised to 7-11% during hypoxaemia. 4 It is concluded that nicotine and tobacco smoke cause augmentation of myocardial oxygen supply, even during moderate hypoxaemia. By contrast, smoking dosages of carbon monoxide have the potential of producing a small reduction of MPo2 during normoxia, but the effect is negligible during moderate hypoxaemia. PMID:656704

  18. Outcome of veno-venous extracorporeal membrane oxygenation use in acute respiratory distress syndrome after cardiac surgery with cardiopulmonary bypass

    PubMed Central

    Song, Joo Han; Woo, Won Ki; Song, Seung Hwan; Kim, Hyo Hyun; Kim, Bong Joon; Kim, Ha Eun; Kim, Do Jung; Suh, Jee Won; Shin, Yu Rim; Park, Han Ki; Lee, Seung Hyun; Joo, Hyun Chel; Lee, Sak; Chang, Byung Chul; Yoo, Kyung Jong; Kim, Young Sam

    2016-01-01

    Background Cardiac surgery with cardiopulmonary bypass (CPB) is a known risk factor for acute respiratory distress syndrome (ARDS). We aimed to analyze the treatment outcome in patients who required veno-venous extracorporeal membrane oxygenation (VV-ECMO) for postcardiotomy ARDS despite other rescue modalities. Methods We retrospectively reviewed the outcomes in 13 patients (mean age, 54.7±5.9 years) who received VV-ECMO support for refractory ARDS after cardiac surgery between March 2013 and February 2016 at Severance Hospital, Yonsei University (Seoul, Korea). Results At the start of VV-ECMO, the average lung injury score was 3.0±0.2, and the Respiratory Extracorporeal Membrane Oxygenation Survival Prediction (RESP) score was −4±1.1. Although 7 patients initiated VV-ECMO support within 24 h from operation, the remaining 6 started at a median of 8.5 days (range, 5−16 days). Nine (69.3%) patients were successfully weaned from VV-ECMO. After a median follow-up duration of 14.5 months (range, 1.0−33.0 months) for survivors, the 1-year overall survival was 58.6%±14.4%. The differences in the overall survival from VV-ECMO according to the RESP score risk classes were borderline significant (100% in class III, 50%±25% in class IV, and 20%±17.9% in class V; P=0.088). Conclusions VV-ECMO support can be a feasible rescue strategy for adult patients who develop refractory ARDS after a cardiac surgery. Additionally, the RESP score seems a valuable prognostic tool for post-ECMO survival outcome in this patient population as well. PMID:27499972

  19. Efficacy of high-flow oxygen by nasal cannula with active humidification in a patient with acute respiratory failure of neuromuscular origin.

    PubMed

    Díaz-Lobato, Salvador; Folgado, Miguel Angel; Chapa, Angel; Mayoralas Alises, Sagrario

    2013-12-01

    The treatment of choice for patients with respiratory failure of neuromuscular origin, especially in patients with hypercapnic respiratory acidosis, is noninvasive ventilation (NIV). Endotracheal intubation and invasive ventilation are indicated for patients with severe respiratory compromise or failure of NIV. In recent years, high-flow oxygen therapy and active humidification devices have been introduced, and emerging evidence suggests that high-flow oxygen may be effective in various clinical settings, such as acute respiratory failure, after cardiac surgery, during sedation and analgesia, in acute heart failure, in hypoxemic respiratory distress, in do-not-intubate patients, in patients with chronic cough and copious secretions, pulmonary fibrosis, or cancer, in critical areas and the emergency department. We report on a patient with amyotrophic lateral sclerosis who arrived at the emergency department with acute hypercapnic respiratory failure. She did not tolerate NIV and refused intubation, but was treated successfully with heated, humidified oxygen via high-flow nasal cannula. Arterial blood analysis after an hour on high-flow nasal cannula showed improved pH, P(aCO2), and awareness. The respiratory acidosis was corrected, and she was discharged after 5 days of hospitalization. Her response to high-flow nasal cannula was similar to that expected with NIV. We discuss the mechanisms of action of heated, humidified high-flow oxygen therapy.

  20. Extracorporeal Membrane Oxygenation as Bridge-to-Decision in Acute Heart Failure due to Systemic Light-Chain Amyloidosis

    PubMed Central

    Silva, Jennifer Mancio; Fontes-Carvalho, Ricardo; Valente, Dília; Almeida, Cristiana; Cruz, António José; Tente, David; Coelho, Henrique; Oliveira, Marco; Albuquerque, Aníbal; Ribeiro, Vasco Gama

    2015-01-01

    Patient: Female, 58 Final Diagnosis: Acute hear failure Symptoms: Dispnoea • edema • fatigue Medication: — Clinical Procedure: Bone marrow biopsy • endomyocardial biopsy • abdominal subcutaneous fat biopsy under ECMO support Specialty: Cardiology Objective: Rare disease Background: Cardiac amyloidosis results from the amyloid deposition in heart tissue, either in the context of a systemic disease or as a localized form. Several pro-amyloid proteins can produce amyloid deposits in the heart. Each of these amyloidoses has characteristic clinical (cardiac and extracardiac) features, and a specific diagnosis and treatment. Case Report: A 58-year-old woman who presented with acute heart failure and echocardiographic findings strongly suggestive of infiltrative cardiomyopathy needed percutaneous veno-arterial extracorporeal membrane oxygenation (ECMO) as bridge-to-decision. Amyloid deposition was found on endomyocardial and bone marrow biopsies. Bone marrow plasma cell infiltrate with acute renal lesion and hypercalcemia confirmed the diagnosis of multiple myeloma-associated systemic light-chain amyloidosis (AL). Refractory shock with multi-organic failure syndrome persisted and no improvements in left ventricular function and structure were seen. After extensive discussion by a multidisciplinary team, and with the patients’ family, she was not considered eligible for high-dose chemotherapy and/or autologous stem cell transplantation, heart transplantation, or sequential heart with autologous stem cell transplantation. The patient died a few hours after ECMO withdrawal. During the 14 days of ECMO support no major bleeding or thrombotic complications occurred. Conclusions: The clinician must consider a diagnosis of cardiac amyloidosis in patients with heart failure, a restrictive type of cardiomyopathy with ventricular hypertrophy in the absence of valve abnormalities, or uncontrolled arterial hypertension. Although developments in chemotherapy have greatly

  1. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Influence of Oxygen Pressure on Structural and Sensing Properties of β-Ga2O3 Nanomaterial by Thermal Evaporation

    NASA Astrophysics Data System (ADS)

    Ma, Hai-Lin; Fan, Duo-Wang

    2009-11-01

    We prepare the gallium oxide (β-Ga2O3) nanomaterials from gallium and oxygen by thermal evaporation in the argon atmosphere and research their oxygen sensing under UV illumination with different oxygen pressures. X-ray diffraction reveals that the synthesized product is monoclinic gallium oxide, it is further confirmed by electron diffraction of transmission electron microscope, and its morphology through the observation using scanning electron microscope reveals that β-Ga2O3 nanobelts with a breadth less than 100 nm and length of several micrometers are synthesized under low oxygen pressure, while the nano/microbelts are synthesized under high oxygen pressure. Room-temperature oxygen sensing is tested under at 254 nm illumination and it is found that the current decreases quickly first and then slowly with oxygen pressure from low to high.

  2. Acute supplementation of N-acetylcysteine does not affect muscle blood flow and oxygenation characteristics during handgrip exercise.

    PubMed

    Smith, Joshua R; Broxterman, Ryan M; Ade, Carl J; Evans, Kara K; Kurti, Stephanie P; Hammer, Shane M; Barstow, Thomas J; Harms, Craig A

    2016-04-01

    N-acetylcysteine (NAC; antioxidant and thiol donor) supplementation has improved exercise performance and delayed fatigue, but the underlying mechanisms are unknown. One possibility isNACsupplementation increases limb blood flow during severe-intensity exercise. The purpose was to determine ifNACsupplementation affected exercising arm blood flow and muscle oxygenation characteristics. We hypothesized thatNACwould lead to higher limb blood flow and lower muscle deoxygenation characteristics during severe-intensity exercise. Eight healthy nonendurance trained men (21.8 ± 1.2 years) were recruited and completed two constant power handgrip exercise tests at 80% peak power until exhaustion. Subjects orally consumed either placebo (PLA) orNAC(70 mg/kg) 60 min prior to handgrip exercise. Immediately prior to exercise, venous blood samples were collected for determination of plasma redox balance. Brachial artery blood flow (BABF) was measured via Doppler ultrasound and flexor digitorum superficialis oxygenation characteristics were measured via near-infrared spectroscopy. FollowingNACsupplementaiton, plasma cysteine (NAC: 47.2 ± 20.3 μmol/L vs.PLA: 9.6 ± 1.2 μmol/L;P = 0.001) and total cysteine (NAC: 156.2 ± 33.9 μmol/L vs.PLA: 132.2 ± 16.3 μmol/L;P = 0.048) increased. Time to exhaustion was not significantly different (P = 0.55) betweenNAC(473.0 ± 62.1 sec) andPLA(438.7 ± 58.1 sec). RestingBABFwas not different (P = 0.79) withNAC(99.3 ± 31.1 mL/min) andPLA(108.3 ± 46.0 mL/min).BABFwas not different (P = 0.42) during exercise or at end-exercise (NAC: 413 ± 109 mL/min;PLA: 445 ± 147 mL/min). Deoxy-[hemoglobin+myoglobin] and total-[hemoglobin+myoglobin] were not significantly different (P = 0.73 andP = 0.54, respectively) at rest or during exercise between conditions. We conclude that acuteNACsupplementation does not alter oxygen delivery during exercise in men.

  3. Position paper for the organization of extracorporeal membrane oxygenation programs for acute respiratory failure in adult patients.

    PubMed

    Combes, Alain; Brodie, Daniel; Bartlett, Robert; Brochard, Laurent; Brower, Roy; Conrad, Steve; De Backer, Daniel; Fan, Eddy; Ferguson, Niall; Fortenberry, James; Fraser, John; Gattinoni, Luciano; Lynch, William; MacLaren, Graeme; Mercat, Alain; Mueller, Thomas; Ogino, Mark; Peek, Giles; Pellegrino, Vince; Pesenti, Antonio; Ranieri, Marco; Slutsky, Arthur; Vuylsteke, Alain

    2014-09-01

    The use of extracorporeal membrane oxygenation (ECMO) for severe acute respiratory failure (ARF) in adults is growing rapidly given recent advances in technology, even though there is controversy regarding the evidence justifying its use. Because ECMO is a complex, high-risk, and costly modality, at present it should be conducted in centers with sufficient experience, volume, and expertise to ensure it is used safely. This position paper represents the consensus opinion of an international group of physicians and associated health-care workers who have expertise in therapeutic modalities used in the treatment of patients with severe ARF, with a focus on ECMO. The aim of this paper is to provide physicians, ECMO center directors and coordinators, hospital directors, health-care organizations, and regional, national, and international policy makers a description of the optimal approach to organizing ECMO programs for ARF in adult patients. Importantly, this will help ensure that ECMO is delivered safely and proficiently, such that future observational and randomized clinical trials assessing this technique may be performed by experienced centers under homogeneous and optimal conditions. Given the need for further evidence, we encourage restraint in the widespread use of ECMO until we have a better appreciation for both the potential clinical applications and the optimal techniques for performing ECMO.

  4. Myocardial protection of early extracorporeal membrane oxygenation (ECMO) support for acute myocardial infarction with cardiogenic shock in pigs.

    PubMed

    Zhu, Gang-jie; Sun, Li-na; Li, Xing-hai; Wang, Ning-fu; Wu, Hong-hai; Yuan, Chen-xing; Li, Qiao-qiao; Xu, Peng; Ren, Ya-qi; Mao, Bao-gen

    2015-09-01

    The aim of this study was to explore myocardial protection of early extracorporeal membrane oxygenation (ECMO) support for acute myocardial infarction with cardiogenic shock in pigs. 24 male pigs (34.6 ± 1.3 kg) were randomly divided into three groups-control group, drug therapy group, and ECMO group. Myocardial infarction model was created in drug therapy group and ECMO group by ligating coronary artery. When cardiogenic shock occurred, drugs were given in drug therapy group and ECMO began to work in ECMO group. The pigs were killed 24 h after cardiogenic shock. Compared with in drug therapy group, left ventricular end-diastolic pressure in ECMO group decreased significantly 6 h after ligation (P < 0.05). At the end of the experiments, LV - dp/dt among three groups was significantly different, drug therapy group < ECMO group < control group. There was no difference in LV + dp/dt between drug therapy group and ECMO group. Compared with drug group, myocardial infarct size of ECMO group did not reduce significantly, but myocardial enzyme and troponin-I decreased significantly. Compared with drug therapy, ECMO improves left ventricular diastolic function, and may improve systolic function. ECMO cannot reduce myocardial infarct size without revascularization, but may have positive effects on ischemic areas by avoiding further injuring.

  5. Sol-gel synthesized Sr4Al14O25:Eu2+/Dy3+ blue-green phosphorous as oxygen sensing materials

    NASA Astrophysics Data System (ADS)

    Aydin, Ilkyaz; Ertekin, Kadriye; Demirci, Selim; Gultekin, Serdar; Celik, Erdal

    2016-12-01

    In this study, we utilized newly synthesized Sr4Al14O25:Eu2+/Dy3+ blue-green phosphors along with silver nanoparticles (AgNPs) for fabrication of oxygen sensitive materials. To the best of our knowledge oxygen sensing mechanism of the offered design is totally different from the previously published works. One-component silicone: poly (1-trimethylsilyl-1-propyne), two component phenyl bearing silicone, plasticized polymethylmethacrylate, and ethylcellulose (EC) were tested as matrix materials. Electrospun fibers, porous and smooth thin films were produced by electrospinning or knife coating technique. Oxygen induced luminescence of the phosphors at 544 nm was followed as the analytical signal. Utilization of silver nanoparticles in silicone along with phosphors resulted with a 7.14 fold enhancement in the signal intensity and significant spectral response towards oxygen competing with the signals of the oxygen sensors utilizing metalloporphyrins or ruthenium complexes. We observed high sensitivity and stability, increased surface area and an enhancement in all sensor dynamics. Linearity of the calibration plots was superior for the pO2 range of 0.0-20.0% with respect to the previously reported ones. When stored at the ambient air of the laboratory there was no significant drift in signal intensity after 12 months. Our sensitivity and stability tests are still in progress.

  6. Analysis of the hypoxia-induced ADH2 promoter of the respiratory yeast Pichia stipitis reveals a new mechanism for sensing of oxygen limitation in yeast.

    PubMed

    Passoth, Volkmar; Cohn, Marita; Schäfer, Bernd; Hahn-Hägerdal, Bärbel; Klinner, Ulrich

    2003-01-15

    We introduced a reporter gene system into Pichia stipitis using the gene for the artificial green fluorescent protein (GFP), variant yEGFP. This system was used to analyse hypoxia-dependent PsADH2 regulation. Reporter gene activity was only found under oxygen limitation on a fermentable carbon source. The promoter was not induced by oxygen limitation in the Crabtree-positive yeast Saccharomyces cerevisiae. Promoter deletions revealed that a region of 15 bp contained the essential site for hypoxic induction. This motif was different from the known hypoxia response elements of S. cerevisiae but showed some similarity to the mammalian HIF-1 binding site. Electrophoretic mobility shift assays demonstrated specific protein binding to this region under oxygen limitation. Similar to the S. cerevisiae heme sensor system, the promoter was induced by Co(2+). Cyanide was not able to mimic the effect of oxygen limitation. The activation mechanism of PsADH2 also, in this respect, has similarities to the mammalian HIF-1 system, which is inducible by Co(2+) but not by cyanide. Thus, the very first promoter analysis in P. stipitis revealed a hitherto unknown mechanism of oxygen sensing in yeast.

  7. [Altitude, the ratio of PaO2 to fraction of inspired oxygen, and shunt: impact on the assessment of acute lung injury].

    PubMed

    Pérez-Padilla, J R

    2004-10-01

    The ratio of PaO2 to the fraction of inspired oxygen (PaO2/FIO2) is commonly used to determine the severity of acute lung injury and acute respiratory distress syndrome (ARDS). The research presented here used computational models of the lung to analyze the effect of altitude on the PaO2/FIO2 ratio and pulmonary shunt. At a given shunt, the PaO2/FIO2 ratio is lower at higher altitudes. Therefore, when evaluating for ARDS based on a PaO2/FIO2 ratio of <200 mm Hg, patients residing at high altitudes will have less shunt and, presumably, less severe lung injury than patients at sea level. This should be taken into consideration when comparing patients from different altitudes. Shunt should more often be measured directly or be estimated assuming a constant arteriovenous oxygen content difference.

  8. Protective Role of Proton-Sensing TDAG8 in Lipopolysaccharide-Induced Acute Lung Injury

    PubMed Central

    Tsurumaki, Hiroaki; Mogi, Chihiro; Aoki-Saito, Haruka; Tobo, Masayuki; Kamide, Yosuke; Yatomi, Masakiyo; Sato, Koichi; Dobashi, Kunio; Ishizuka, Tamotsu; Hisada, Takeshi; Yamada, Masanobu; Okajima, Fumikazu

    2015-01-01

    Acute lung injury is characterized by the infiltration of neutrophils into lungs and the subsequent impairment of lung function. Here we explored the role of TDAG8 in lung injury induced by lipopolysaccharide (LPS) administrated intratracheally. In this model, cytokines and chemokines released from resident macrophages are shown to cause neutrophilic inflammation in the lungs. We found that LPS treatment increased TDAG8 expression in the lungs and confirmed its expression in resident macrophages in bronchoalveolar lavage (BAL) fluids. LPS administration remarkably increased neutrophil accumulation without appreciable change in the resident macrophages, which was associated with increased penetration of blood proteins into BAL fluids, interstitial accumulation of inflammatory cells, and damage of the alveolar architecture. The LPS-induced neutrophil accumulation and the associated lung damage were enhanced in TDAG8-deficient mice as compared with those in wild-type mice. LPS also increased several mRNA and protein expressions of inflammatory cytokines and chemokines in the lungs or BAL fluids. Among these inflammatory mediators, mRNA and protein expression of KC (also known as CXCL1), a chemokine of neutrophils, were significantly enhanced by TDAG8 deficiency. We conclude that TDAG8 is a negative regulator for lung neutrophilic inflammation and injury, in part, through the inhibition of chemokine production. PMID:26690120

  9. Protective Role of Proton-Sensing TDAG8 in Lipopolysaccharide-Induced Acute Lung Injury.

    PubMed

    Tsurumaki, Hiroaki; Mogi, Chihiro; Aoki-Saito, Haruka; Tobo, Masayuki; Kamide, Yosuke; Yatomi, Masakiyo; Sato, Koichi; Dobashi, Kunio; Ishizuka, Tamotsu; Hisada, Takeshi; Yamada, Masanobu; Okajima, Fumikazu

    2015-12-04

    Acute lung injury is characterized by the infiltration of neutrophils into lungs and the subsequent impairment of lung function. Here we explored the role of TDAG8 in lung injury induced by lipopolysaccharide (LPS) administrated intratracheally. In this model, cytokines and chemokines released from resident macrophages are shown to cause neutrophilic inflammation in the lungs. We found that LPS treatment increased TDAG8 expression in the lungs and confirmed its expression in resident macrophages in bronchoalveolar lavage (BAL) fluids. LPS administration remarkably increased neutrophil accumulation without appreciable change in the resident macrophages, which was associated with increased penetration of blood proteins into BAL fluids, interstitial accumulation of inflammatory cells, and damage of the alveolar architecture. The LPS-induced neutrophil accumulation and the associated lung damage were enhanced in TDAG8-deficient mice as compared with those in wild-type mice. LPS also increased several mRNA and protein expressions of inflammatory cytokines and chemokines in the lungs or BAL fluids. Among these inflammatory mediators, mRNA and protein expression of KC (also known as CXCL1), a chemokine of neutrophils, were significantly enhanced by TDAG8 deficiency. We conclude that TDAG8 is a negative regulator for lung neutrophilic inflammation and injury, in part, through the inhibition of chemokine production.

  10. Sensing properties of an oxygen sensor using BaCe{sub 0.8}Gd{sub 0.2}O{sub 3{minus}{alpha}} ceramics as electrolytes

    SciTech Connect

    Taniguchi, Noboru; Yasumoto, Eiichi; Nakagiri, Yasushi; Gamo, Takaharu

    1998-05-01

    Limiting-current-type oxygen sensors using BaCe{sub 0.8}Gd{sub 0.2}O{sub 3{minus}{alpha}} (BCG) ceramics as electrolytes were constructed on a trial basis and their sensing properties investigated in order to develop a new oxygen sensor to replace the zirconia type. BCG ceramics exhibited high conductivity in the temperature range 200--1,000 C, and it was verified that the oxide ion could be a conductive carrier in BCG in oxygen at low temperatures (300 C). The oxygen sensors using BCGs worked at 300 C, and their output currents linearly increased with an increase in oxygen concentration in the range 1--22%. They could respond within 30 s between 1 and 21%, and humidity only slightly affected sensing performance. BCG seems to be a promising electrolyte material for an oxygen sensor operating at low temperatures (300 C).

  11. Acute on-chip HIV detection through label-free electrical sensing of viral nano-lysate.

    PubMed

    Shafiee, Hadi; Jahangir, Muntasir; Inci, Fatih; Wang, Shuqi; Willenbrecht, Remington B M; Giguel, Francoise F; Tsibris, Athe M N; Kuritzkes, Daniel R; Demirci, Utkan

    2013-08-12

    Development of portable biosensors has broad applications in environmental monitoring, clinical diagnosis, public health, and homeland security. There is an unmet need for pathogen detection at the point-of-care (POC) using a fast, sensitive, inexpensive, and easy-to-use method that does not require complex infrastructure and well-trained technicians. For instance, detection of Human Immunodeficiency Virus (HIV-1) at acute infection stage has been challenging, since current antibody-based POC technologies are not effective due to low concentration of antibodies. In this study, we demonstrated for the first time a label-free electrical sensing method that can detect lysed viruses, i.e. viral nano-lysate, through impedance analysis, offering an alternative technology to the antibody-based methods such as dipsticks and Enzyme-linked Immunosorbent Assay (ELISA). The presented method is a broadly applicable platform technology that can potentially be adapted to detect multiple pathogens utilizing impedance spectroscopy for other infectious diseases including herpes, influenza, hepatitis, pox, malaria, and tuberculosis. The presented method offers a rapid and portable tool that can be used as a detection technology at the POC in resource-constrained settings, as well as hospital and primary care settings.

  12. Aspartate 141 Is the Fourth Ligand of the Oxygen-sensing [4Fe-4S]2+ Cluster of Bacillus subtilis Transcriptional Regulator Fnr*

    PubMed Central

    Gruner, Ines; Frädrich, Claudia; Böttger, Lars H.; Trautwein, Alfred X.; Jahn, Dieter; Härtig, Elisabeth

    2011-01-01

    The Bacillus subtilis redox regulator Fnr controls genes of the anaerobic metabolism in response to low oxygen tension. An unusual structure for the oxygen-sensing [4Fe-4S]2+ cluster was detected by a combination of genetic experiments with UV-visible and Mössbauer spectroscopy. Asp-141 was identified as the fourth iron-sulfur cluster ligand besides three Cys residues. Exchange of Asp-141 with Ala abolished functional in vivo complementation of an fnr knock-out strain by the mutagenized fnr gene and in vitro DNA binding of the recombinant regulator FnrD141A. In contrast, substitution of Asp-141 with Cys preserved [4Fe-4S]2+ structure and regulator function. PMID:21068385

  13. Necrostatin-1 protects against reactive oxygen species (ROS)-induced hepatotoxicity in acetaminophen-induced acute liver failure

    PubMed Central

    Takemoto, Kenji; Hatano, Etsuro; Iwaisako, Keiko; Takeiri, Masatoshi; Noma, Naruto; Ohmae, Saori; Toriguchi, Kan; Tanabe, Kazutaka; Tanaka, Hirokazu; Seo, Satoru; Taura, Kojiro; Machida, Keigo; Takeda, Norihiko; Saji, Shigehira; Uemoto, Shinji; Asagiri, Masataka

    2014-01-01

    Excessive acetaminophen (APAP) use is one of the most common causes of acute liver failure. Various types of cell death in the damaged liver are linked to APAP-induced hepatotoxicity, and, of these, necrotic cell death of hepatocytes has been shown to be involved in disease pathogenesis. Until recently, necrosis was commonly considered to be a random and unregulated form of cell death; however, recent studies have identified a previously unknown form of programmed necrosis called receptor-interacting protein kinase (RIPK)-dependent necrosis (or necroptosis), which is controlled by the kinases RIPK1 and RIPK3. Although RIPK-dependent necrosis has been implicated in a variety of disease states, including atherosclerosis, myocardial organ damage, stroke, ischemia–reperfusion injury, pancreatitis, and inflammatory bowel disease. However its involvement in APAP-induced hepatocyte necrosis remains elusive. Here, we showed that RIPK1 phosphorylation, which is a hallmark of RIPK-dependent necrosis, was induced by APAP, and the expression pattern of RIPK1 and RIPK3 in the liver overlapped with that of CYP2E1, whose activity around the central vein area has been demonstrated to be critical for the development of APAP-induced hepatic injury. Moreover, a RIPK1 inhibitor ameliorated APAP-induced hepatotoxicity in an animal model, which was underscored by significant suppression of the release of hepatic enzymes and cytokine expression levels. RIPK1 inhibition decreased reactive oxygen species levels produced in APAP-injured hepatocytes, whereas CYP2E1 expression and the depletion rate of total glutathione were unaffected. Of note, RIPK1 inhibition also conferred resistance to oxidative stress in hepatocytes. These data collectively demonstrated a RIPK-dependent necrotic mechanism operates in the APAP-injured liver and inhibition of this pathway may be beneficial for APAP-induced fulminant hepatic failure. PMID:25349782

  14. Acute resistance exercise with blood flow restriction effects on heart rate, double product, oxygen saturation and perceived exertion.

    PubMed

    Neto, Gabriel R; Sousa, Maria S C; Costa e Silva, Gabriel V; Gil, Ana L S; Salles, Belmiro F; Novaes, Jefferson S

    2016-01-01

    The aim of this study was to compare the acute effect of resistance exercise (RE) with and without blood flow restriction (BFR) on heart rate (HR), double product (DP), oxygen saturation (SpO2 ) and rating of perceived exertion (RPE). Twenty-four men (21·79 ± 3·21 years) performed three experimental protocols in a random order (crossover): (i) high-intensity RE at 80% of 1RM (HI), (ii) low-intensity RE at 20% of 1RM (LI) and (iii) low-intensity RE at 20% of 1RM combined with partial blood flow restriction (LI+BFR). HR, blood pressure, SpO2 and RPE were assessed. The data were analysed using repeated measures analysis of variance and the Wilcoxon test for RPE. The results indicated that all protocols significantly increased HR, both immediately postexercise and during the subsequent 60 min (P<0·05), and postexercise DP (P<0·05), but there were no differences between protocols. The protocols of LI and LI+BFR reduced postexercise SpO2 (P = 0·033, P = 0·007), and the LI+BFR protocol presented a perception of greater exertion in the lower limbs compared with HI (P = 0·022). We conclude that RE performed at low intensity combined with BFR seems to reduce the SpO2 after exercise and increase HR and DP while maintaining a perception of greater exertion on the lower limbs.

  15. Identification of HIF-1 signaling pathway in Pelteobagrus vachelli using RNA-Seq: effects of acute hypoxia and reoxygenation on oxygen sensors, respiratory metabolism, and hematology indices.

    PubMed

    Zhang, Guosong; Zhao, Cheng; Wang, Qintao; Gu, Yichun; Li, Zecheng; Tao, Panfeng; Chen, Jiawei; Yin, Shaowu

    2017-03-28

    Oxygen is a vital element in aquatic environments. The concentration of oxygen to which aquatic organisms are exposed is influenced by salinity, water temperature, weather, and surface water runoff. Hypoxia has a serious effect on fish populations, and can lead to the loss of habitat and die-offs. Therefore, in the present study we used next-generation sequencing technology to characterize the transcriptomes of Pelteobagrus vachelli and identified 70 candidate genes in the HIF-1 signaling pathway that are important for the hypoxic response in all metazoan species. For the first time, the present study reported the effects of acute hypoxia and reoxygenation on oxygen sensors, respiratory metabolism, and hematology indices in P. vachelli. The predicted physiological adjustments show that P. vachelli's blood oxygen-carrying capacity was increased through increased RBC, HB, and SI after hypoxia exposure. Glycolysis-related enzyme activities (PFK, HK, and PK) and LDH in the brain and liver also increased, indicating a rise in anaerobic metabolism. The observed reduction in oxidative enzyme level (CS) in the liver during hypoxia suggests a concomitant depression in aerobic metabolism. There were significant increases in oxygen sensor mRNA expression and HIF-1α protein expression during hypoxia and reoxygenation exposure, suggesting that the HIF-1 signaling pathway was activated in the liver and brain of P. vachelli in response to acute hypoxia and reoxygenation. Our findings suggest that oxygen sensors (e.g., HIF-1α) of P. vachelli are potentially useful biomarkers of environmental hypoxic exposure. These data contribute to a better understanding of the molecular mechanisms of the hypoxia signaling pathway in fish under hypoxia and reoxygenation.

  16. New method of preoxygenation for orotracheal intubation in patients with hypoxaemic acute respiratory failure in the intensive care unit, non-invasive ventilation combined with apnoeic oxygenation by high flow nasal oxygen: the randomised OPTINIV study protocol

    PubMed Central

    Jaber, Samir; Molinari, Nicolas; De Jong, Audrey

    2016-01-01

    Introduction Tracheal intubation in the intensive care unit (ICU) is associated with severe life-threatening complications including severe hypoxaemia. Preoxygenation before intubation has been recommended in order to decrease such complications. Non-invasive ventilation (NIV)-assisted preoxygenation allows increased oxygen saturation during the intubation procedure, by applying a positive end-expiratory pressure (PEEP) to prevent alveolar derecruitment. However, the NIV mask has to be taken off after preoxygenation to allow the passage of the tube through the mouth. The patient with hypoxaemia does not receive oxygen during this period, at risk of major hypoxaemia. High-flow nasal cannula oxygen therapy (HFNC) has a potential for apnoeic oxygenation during the apnoea period following the preoxygenation with NIV. Whether application of HFNC combined with NIV is more effective at reducing oxygen desaturation during the intubation procedure compared with NIV alone for preoxygenation in patients with hypoxaemia in the ICU with acute respiratory failure remains to be established. Methods and analysis The HFNC combined to NIV for decreasing oxygen desaturation during the intubation procedure in patients with hypoxaemia in the ICU (OPTINIV) trial is an investigator-initiated monocentre randomised controlled two-arm trial with assessor-blinded outcome assessment. The OPTINIV trial randomises 50 patients with hypoxaemia requiring orotracheal intubation for acute respiratory failure to receive NIV (pressure support=10, PEEP=5, fractional inspired oxygen (FiO2)=100%) combined with HFNC (flow=60 L/min, FiO2=100%, interventional group) or NIV alone (reference group) for preoxygenation. The primary outcome is lowest oxygen saturation during the intubation procedure. Secondary outcomes are intubation-related complications, quality of preoxygenation and ICU mortality. Ethics and dissemination The study project has been approved by the appropriate ethics committee (CPP Sud

  17. Acute administration of high doses of taurine does not substantially improve high-intensity running performance and the effect on maximal accumulated oxygen deficit is unclear.

    PubMed

    Milioni, Fabio; Malta, Elvis de Souza; Rocha, Leandro George Spinola do Amaral; Mesquita, Camila Angélica Asahi; de Freitas, Ellen Cristini; Zagatto, Alessandro Moura

    2016-05-01

    The aim of the present study was to investigate the effects of acute administration of taurine overload on time to exhaustion (TTE) of high-intensity running performance and alternative maximal accumulated oxygen deficit (MAODALT). The study design was a randomized, placebo-controlled, crossover design. Seventeen healthy male volunteers (age: 25 ± 6 years; maximal oxygen uptake: 50.5 ± 7.6 mL·kg(-1)·min(-1)) performed an incremental treadmill-running test until voluntary exhaustion to determine maximal oxygen uptake and exercise intensity at maximal oxygen uptake. Subsequently, participants completed randomly 2 bouts of supramaximal treadmill-running at 110% exercise intensity at maximal oxygen uptake until exhaustion (placebo (6 g dextrose) or taurine (6 g) supplementation), separated by 1 week. MAODALT was determined using a single supramaximal effort by summating the contribution of the phosphagen and glycolytic pathways. When comparing the results of the supramaximal trials (i.e., placebo and taurine conditions) no differences were observed for high-intensity running TTE (237.70 ± 66.00 and 277.30 ± 40.64 s; p = 0.44) and MAODALT (55.77 ± 8.22 and 55.06 ± 7.89 mL·kg(-1); p = 0.61), which seem to indicate trivial and unclear differences using the magnitude-based inferences approach, respectively. In conclusion, acute 6 g taurine supplementation before exercise did not substantially improve high-intensity running performance and showed an unclear effect on MAODALT.

  18. Oxygen Mapping within Healthy and Acutely Infarcted Brain Tissue in Humans Using the NMR Relaxation of Lipids: A Proof-Of-Concept Translational Study.

    PubMed

    Colliez, Florence; Safronova, Marta M; Magat, Julie; Joudiou, Nicolas; Peeters, André P; Jordan, Bénédicte F; Gallez, Bernard; Duprez, Thierry

    2015-01-01

    The clinical applicability of brain oxygenation mapping using the MOBILE (Mapping of Oxygen By Imaging Lipids relaxation Enhancement) magnetic resonance (MR) technique was assessed in the clinical setting of normal brain and of acute cerebral ischemia as a founding proof-of-concept translational study. Changes in the oxygenation level within healthy brain tissue can be detected by analyzing the spin-lattice proton relaxation ('Global T1' combining water and lipid protons) because of the paramagnetic properties of molecular oxygen. It was hypothesized that selective measurement of the relaxation of the lipid protons ('Lipids T1') would result in enhanced sensitivity of pO2 mapping because of higher solubility of oxygen in lipids than in water, and this was demonstrated in pre-clinical models using the MOBILE technique. In the present study, 12 healthy volunteers and eight patients with acute (48-72 hours) brain infarction were examined with the same clinical 3T MR system. Both Lipids R1 (R1 = 1/T1) and Global R1 were significantly different in the infarcted area and the contralateral unaffected brain tissue, with a higher statistical significance for Lipids R1 (median difference: 0.408 s-1; p<0.0001) than for Global R1 (median difference: 0.154 s-1; p = 0.027). Both Lipids R1 and Global R1 values in the unaffected contralateral brain tissue of stroke patients were not significantly different from the R1 values calculated in the brain tissue of healthy volunteers. The main limitations of the present prototypic version of the MOBILE sequence are the long acquisition time (4 min), hampering robustness of data in uncooperative patients, and a 2 mm slice thickness precluding accurate measurements in small infarcts because of partial volume averaging effects.

  19. Enhancing dissolved oxygen control using an on-line hybrid fuzzy-neural soft-sensing model-based control system in an anaerobic/anoxic/oxic process.

    PubMed

    Huang, Mingzhi; Wan, Jinquan; Hu, Kang; Ma, Yongwen; Wang, Yan

    2013-12-01

    An on-line hybrid fuzzy-neural soft-sensing model-based control system was developed to optimize dissolved oxygen concentration in a bench-scale anaerobic/anoxic/oxic (A(2)/O) process. In order to improve the performance of the control system, a self-adapted fuzzy c-means clustering algorithm and adaptive network-based fuzzy inference system (ANFIS) models were employed. The proposed control system permits the on-line implementation of every operating strategy of the experimental system. A set of experiments involving variable hydraulic retention time (HRT), influent pH (pH), dissolved oxygen in the aerobic reactor (DO), and mixed-liquid return ratio (r) was carried out. Using the proposed system, the amount of COD in the effluent stabilized at the set-point and below. The improvement was achieved with optimum dissolved oxygen concentration because the performance of the treatment process was optimized using operating rules implemented in real time. The system allows various expert operational approaches to be deployed with the goal of minimizing organic substances in the outlet while using the minimum amount of energy.

  20. Ratiometric Molecular Probes Based on Dual Emission of a Blue Fluorescent Coumarin and a Red Phosphorescent Cationic Iridium(III) Complex for Intracellular Oxygen Sensing.

    PubMed

    Yoshihara, Toshitada; Murayama, Saori; Tobita, Seiji

    2015-06-09

    Ratiometric molecular probes RP1 and RP2 consisting of a blue fluorescent coumarin and a red phosphorescent cationic iridium complex connected by a tetra- or octaproline linker, respectively, were designed and synthesized for sensing oxygen levels in living cells. These probes exhibited dual emission with good spectral separation in acetonitrile. The photorelaxation processes, including intramolecular energy transfer, were revealed by emission quantum yield and lifetime measurements. The ratios (R(I) = (I(p)/I(f))) between the phosphorescence (I(p)) and fluorescence (I(f)) intensities showed excellent oxygen responses; the ratio of R(I) under degassed and aerated conditions ( R(I)(0) was 20.3 and 19.6 for RP1 and RP2. The introduction of the cationic Ir (III) complex improved the cellular uptake efficiency compared to that of a neutral analogue with a tetraproline linker. The emission spectra of the ratiometric probes internalized into living HeLa or MCF-7 cells could be obtained using a conventional microplate reader. The complex RP2 with an octaproline linker provided ratios comparable to the ratiometric measurements obtained using a microplate reader: the ratio of the R(I)) value of RP2 under hypoxia (2.5% O2) to that under normoxia (21% O2) was 1.5 and 1.7 for HeLa and MCF-7 cells, respectively. Thus, the intracellular oxygen levels of MCF-7 cells could be imaged by ratiometric emission measurements using the complex RP2.

  1. Ratiometric Molecular Probes Based on Dual Emission of a Blue Fluorescent Coumarin and a Red Phosphorescent Cationic Iridium(III) Complex for Intracellular Oxygen Sensing

    PubMed Central

    Yoshihara, Toshitada; Murayama, Saori; Tobita, Seiji

    2015-01-01

    Ratiometric molecular probes RP1 and RP2 consisting of a blue fluorescent coumarin and a red phosphorescent cationic iridium complex connected by a tetra- or octaproline linker, respectively, were designed and synthesized for sensing oxygen levels in living cells. These probes exhibited dual emission with good spectral separation in acetonitrile. The photorelaxation processes, including intramolecular energy transfer, were revealed by emission quantum yield and lifetime measurements. The ratios (RI=(Ip/If)) between the phosphorescence (Ip) and fluorescence (If) intensities showed excellent oxygen responses; the ratio of RI under degassed and aerated conditions (RI0/RI) was 20.3 and 19.6 for RP1 and RP2. The introduction of the cationic Ir (III) complex improved the cellular uptake efficiency compared to that of a neutral analogue with a tetraproline linker. The emission spectra of the ratiometric probes internalized into living HeLa or MCF-7 cells could be obtained using a conventional microplate reader. The complex RP2 with an octaproline linker provided ratios comparable to the ratiometric measurements obtained using a microplate reader: the ratio of the RI value of RP2 under hypoxia (2.5% O2) to that under normoxia (21% O2) was 1.5 and 1.7 for HeLa and MCF-7 cells, respectively. Thus, the intracellular oxygen levels of MCF-7 cells could be imaged by ratiometric emission measurements using the complex RP2. PMID:26066988

  2. Influence of samaria doping on the resistance of ceria thin films and its implications to the planar oxygen sensing devices

    SciTech Connect

    Gupta, Shilpi; Kuchibhatla, Satyanarayana V N T; Engelhard, Mark H.; Shutthanandan, V.; Nachimuthu, Ponnusamy; Jiang, Weilin; Saraf, Laxmikant V.; Thevuthasan, Suntharampillai; Prasad, Shalini

    2009-05-27

    In order to evaluate and analyze the effect of samarium (Sm) doping on the resistance of cerium oxide, we have grown highly oriented samaria doped ceria (SDC) thin films on sapphire, Al2O3 (0001) substrates by using oxygen plasma-assisted molecular beam epitaxy (OPA-MBE). The film growth was monitored using reflection high-energy electron diffraction (RHEED) which shows two-dimensional growth throughout the deposition. Following growth, the thin films were characterized by X-ray photoelectron spectroscopy (XPS), high-resolution X-ray diffraction (HRXRD), and Rutherford backscattering spectrometry (RBS). XPS depth-profile shows Sm atoms are uniformly distributed in ceria lattice throughout the bulk of the film. The valence states of Ce and Sm in doped thin films are found to be Ce4+ and Sm3+, respectively. HRXRD shows the samaria doped ceria films on Al2O3(0001) exhibit (111) preferred orientation. Ion-channeling in RBS measurements confirms high quality of the thin films. The resistance of the samaria doped ceria films, obtained by two probe measurement capability under various oxygen pressure (1mTorr-100Torr) and temperatures (623K to 973K), is significantly lower than that of pure ceria under same conditions. The 6Sm% doped ceria film is the optimum composition for highest conductivity. This is attributed to the increased oxygen vacant sites in fluorite crystal structure of the epitaxial thin films which facilitate faster oxygen diffusion through hopping process.

  3. Usefulness of hyperbaric oxygen therapy to inhibit restenosis after percutaneous coronary intervention for acute myocardial infarction or unstable angina pectoris.

    PubMed

    Sharifi, Mohsen; Fares, Wassim; Abdel-Karim, Isam; Koch, J Michael; Sopko, Joseph; Adler, Dale

    2004-06-15

    The purpose of this trial was to assess whether the addition of hyperbaric oxygen to percutaneous coronary intervention can reduce clinical restenosis. Major adverse cardiac events at 8 months were found in only 1 of 24 patients (4%) who received hyperbaric oxygen compared with 13 of 37 patients (35%) who did not.

  4. Oxygen Sensing in Drosophila: Multiple Isoforms of the Prolyl Hydroxylase Fatiga Have Different Capacity to Regulate HIFα/Sima

    PubMed Central

    Dekanty, Andrés; Wappner, Pablo

    2010-01-01

    Background The Hypoxia Inducible Factor (HIF) mediates cellular adaptations to low oxygen. Prolyl-4-hydroxylases are oxygen sensors that hydroxylate the HIF alpha-subunit, promoting its proteasomal degradation in normoxia. Three HIF-prolyl hydroxylases, encoded by independent genes, PHD1, PHD2, and PHD3, occur in mammals. PHD2, the longest PHD isoform includes a MYND domain, whose biochemical function is unclear. PHD2 and PHD3 genes are induced in hypoxia to shut down HIF dependent transcription upon reoxygenation, while expression of PHD1 is oxygen-independent. The physiologic significance of the diversity of the PHD oxygen sensors is intriguing. Methodology and Principal Findings We have analyzed the Drosophila PHD locus, fatiga, which encodes 3 isoforms, FgaA, FgaB and FgaC that are originated through a combination of alternative initiation of transcription and alternative splicing. FgaA includes a MYND domain and is homologous to PHD2, while FgaB and FgaC are shorter isoforms most similar to PHD3. Through a combination of genetic experiments in vivo and molecular analyses in cell culture, we show that fgaB but not fgaA is induced in hypoxia, in a Sima-dependent manner, through a HIF-Responsive Element localized in the first intron of fgaA. The regulatory capacity of FgaB is stronger than that of FgaA, as complete reversion of fga loss-of-function phenotypes is observed upon transgenic expression of the former, and only partial rescue occurs after expression of the latter. Conclusions and Significance Diversity of PHD isoforms is a conserved feature in evolution. As in mammals, there are hypoxia-inducible and non-inducible Drosophila PHDs, and a fly isoform including a MYND domain co-exists with isoforms lacking this domain. Our results suggest that the isoform devoid of a MYND domain has stronger regulatory capacity than that including this domain. PMID:20811646

  5. In vivo imaging of hemodynamics and oxygen metabolism in acute focal cerebral ischemic rats with laser speckle imaging and functional photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Deng, Zilin; Wang, Zhen; Yang, Xiaoquan; Luo, Qingming; Gong, Hui

    2012-08-01

    Stroke is a devastating disease. The changes in cerebral hemodynamics and oxygen metabolism associated with stroke play an important role in pathophysiology study. But the changes were difficult to describe with a single imaging modality. Here the changes in cerebral blood flow (CBF), cerebral blood volume (CBV), and oxygen saturation (SO2) were yielded with laser speckle imaging (LSI) and photoacoustic microscopy (PAM) during and after 3-h acute focal ischemic rats. These hemodynamic measures were further synthesized to deduce the changes in oxygen extraction fraction (OEF). The results indicate that all the hemodynamics except CBV had rapid declines within 40-min occlusion of middle cerebral artery (MCAO). CBV in arteries and veins first increased to the maximum value of 112.42±36.69% and 130.58±31.01% by 15 min MCAO; then all the hemodynamics had a persistent reduction with small fluctuations during the ischemic. When ischemia lasted for 3 h, CBF in arteries, veins decreased to 17±14.65%, 24.52±20.66%, respectively, CBV dropped to 62±18.56% and 59±18.48%. And the absolute SO2 decreased by 40.52±22.42% and 54.24±11.77%. After 180-min MCAO, the changes in hemodynamics and oxygen metabolism were also quantified. The study suggested that combining LSI and PAM provides an attractive approach for stroke detection in small animal studies.

  6. In vivo imaging of hemodynamics and oxygen metabolism in acute focal cerebral ischemic rats with laser speckle imaging and functional photoacoustic microscopy.

    PubMed

    Deng, Zilin; Wang, Zhen; Yang, Xiaoquan; Luo, Qingming; Gong, Hui

    2012-08-01

    Stroke is a devastating disease. The changes in cerebral hemodynamics and oxygen metabolism associated with stroke play an important role in pathophysiology study. But the changes were difficult to describe with a single imaging modality. Here the changes in cerebral blood flow (CBF), cerebral blood volume (CBV), and oxygen saturation (SO2) were yielded with laser speckle imaging (LSI) and photoacoustic microscopy (PAM) during and after 3-h acute focal ischemic rats. These hemodynamic measures were further synthesized to deduce the changes in oxygen extraction fraction (OEF). The results indicate that all the hemodynamics except CBV had rapid declines within 40-min occlusion of middle cerebral artery (MCAO). CBV in arteries and veins first increased to the maximum value of 112.42 ± 36.69% and 130.58 ± 31.01% by 15 min MCAO; then all the hemodynamics had a persistent reduction with small fluctuations during the ischemic. When ischemia lasted for 3 h, CBF in arteries, veins decreased to 17 ± 14.65%, 24.52 ± 20.66%, respectively, CBV dropped to 62 ± 18.56% and 59 ± 18.48%. And the absolute SO2 decreased by 40.52 ± 22.42% and 54.24 ± 11.77%. After 180-min MCAO, the changes in hemodynamics and oxygen metabolism were also quantified. The study suggested that combining LSI and PAM provides an attractive approach for stroke detection in small animal studies.

  7. Temperature, Oxygen, and Salt-Sensing Neurons in C. elegans Are Carbon Dioxide Sensors that Control Avoidance Behavior

    PubMed Central

    Bretscher, Andrew Jonathan; Kodama-Namba, Eiji; Busch, Karl Emanuel; Murphy, Robin Joseph; Soltesz, Zoltan; Laurent, Patrick; de Bono, Mario

    2011-01-01

    Summary Homeostatic control of body fluid CO2 is essential in animals but is poorly understood. C. elegans relies on diffusion for gas exchange and avoids environments with elevated CO2. We show that C. elegans temperature, O2, and salt-sensing neurons are also CO2 sensors mediating CO2 avoidance. AFD thermosensors respond to increasing CO2 by a fall and then rise in Ca2+ and show a Ca2+ spike when CO2 decreases. BAG O2 sensors and ASE salt sensors are both activated by CO2 and remain tonically active while high CO2 persists. CO2-evoked Ca2+ responses in AFD and BAG neurons require cGMP-gated ion channels. Atypical soluble guanylate cyclases mediating O2 responses also contribute to BAG CO2 responses. AFD and BAG neurons together stimulate turning when CO2 rises and inhibit turning when CO2 falls. Our results show that C. elegans senses CO2 using functionally diverse sensory neurons acting homeostatically to minimize exposure to elevated CO2. PMID:21435556

  8. Cellular oxygen sensing: Importins and exportins are mediators of intracellular localisation of prolyl-4-hydroxylases PHD1 and PHD2

    SciTech Connect

    Steinhoff, Amrei; Pientka, Friederike Katharina; Moeckel, Sylvia; Kettelhake, Antje; Hartmann, Enno; Koehler, Matthias; Depping, Reinhard

    2009-10-02

    Hypoxia-inducible factors are crucial in the regulatory process of oxygen homeostasis of vertebrate cells. Inhibition of prolyl hydroxylation of HIF-{alpha} subunits by prolyl-hydroxylases (PHD1, PHD2 and PHD3) leads to transcription of a greater number of hypoxia responsive genes. We have investigated the subcellular distribution and the molecular mechanisms regulating the intracellular allocation of PHD1 and PHD2. As reported earlier we find PHD1 located exclusively in the nucleus. We demonstrate that nuclear import of PHD1 occurs importin {alpha}/{beta} dependently and relies on a nuclear localisation signal (NLS). By contrast PHD2 is cycling between nucleus and cytoplasm, and nuclear import seems to be independent of 'classical' importin {alpha}/{beta} receptors. Furthermore, we reveal that the exit of PHD2 from the nucleus requires CRM1 and the N-terminal 100 amino acids of the protein. Our findings provide new insights into the mechanisms of the regulation of the oxygen sensor cascade of PHDs in different cellular compartments.

  9. Novel perspectives on the PHD-HIF oxygen sensing pathway in cardioprotection mediated by IPC and RIPC.

    PubMed

    Martin-Puig, Silvia; Tello, Daniel; Aragonés, Julián

    2015-01-01

    Reperfusion of ischemic cardiac tissue is the standard treatment for improving clinical outcome following myocardial infarction but is inevitably associated with ischemia-reperfusion injury (IRI). Ischemic myocardial injury can be alleviated by exposing the heart to brief episodes of sublethal ischemia-reperfusion prior to the ischemic insult, a phenomenon that has been termed ischemic preconditioning (IPC). Similarly, remote IPC (RIPC) is defined as transient episodes of ischemia at a distant site before a subsequent prolonged injury of the target organ. In this setting, adaptive responses to hypoxia/ischemia in peripheral tissues include the release of soluble factors that have the potential to protect cardiomyocytes remotely. Oxygen fluctuations is a hallmark of insufficient tissue perfusion and ischemic episodes. Emerging evidence indicates that prolyl hydroxylase oxygen sensors (PHDs) and hypoxia-inducible transcription factors (HIFs) are critical regulators of IPC and RIPC. In this review, we discuss recent findings concerning the role of the PHD-HIF axis in IPC and RIPC-mediated cardioprotection and examine molecular pathways and cell types that might be involved. We also appraise the therapeutic value of targeting the PHD-HIF axis to enhance cardiac tolerance against IRI.

  10. A critical role of acute bronchoconstriction in the mortality associated with high-dose sarin inhalation: Effects of epinephrine and oxygen therapies

    SciTech Connect

    Gundavarapu, Sravanthi; Zhuang, Jianguo; Barrett, Edward G.; Xu, Fadi; Russell, Robert G.; Sopori, Mohan L.

    2014-01-15

    Sarin is an organophosphate nerve agent that is among the most lethal chemical toxins known to mankind. Because of its vaporization properties and ease and low cost of production, sarin is the nerve agent with a strong potential for use by terrorists and rouge nations. The primary route of sarin exposure is through inhalation and, depending on the dose, sarin leads to acute respiratory failure and death. The mechanism(s) of sarin-induced respiratory failure is poorly understood. Sarin irreversibly inhibits acetylcholine esterase, leading to excessive synaptic levels of acetylcholine and, we have previously shown that sarin causes marked ventilatory changes including weakened response to hypoxia. We now show that LD{sub 50} sarin inhalation causes severe bronchoconstriction in rats, leading to airway resistance, increased hypoxia-induced factor-1α, and severe lung epithelium injury. Transferring animals into 60% oxygen chambers after sarin exposure improved the survival from about 50% to 75% at 24 h; however, many animals died within hours after removal from the oxygen chambers. On the other hand, if LD{sub 50} sarin-exposed animals were administered the bronchodilator epinephrine, > 90% of the animals survived. Moreover, while both epinephrine and oxygen treatments moderated cardiorespiratory parameters, the proinflammatory cytokine surge, and elevated expression of hypoxia-induced factor-1α, only epinephrine consistently reduced the sarin-induced bronchoconstriction. These data suggest that severe bronchoconstriction is a critical factor in the mortality induced by LD{sub 50} sarin inhalation, and epinephrine may limit the ventilatory, inflammatory, and lethal effects of sarin. - Highlights: • Inhalation exposure of rats to LD{sub 50} sarin causes death through respiratory failure. • Severe bronchoconstriction is the major cause of sarin-induced respiratory failure. • Transfer of sarin exposed rats to 60% oxygen improves the mortality temporarily.

  11. A critical role of acute bronchoconstriction in the mortality associated with high-dose sarin inhalation: effects of epinephrine and oxygen therapies.

    PubMed

    Gundavarapu, Sravanthi; Zhuang, Jianguo; Barrett, Edward G; Xu, Fadi; Russell, Robert G; Sopori, Mohan L

    2014-01-15

    Sarin is an organophosphate nerve agent that is among the most lethal chemical toxins known to mankind. Because of its vaporization properties and ease and low cost of production, sarin is the nerve agent with a strong potential for use by terrorists and rouge nations. The primary route of sarin exposure is through inhalation and, depending on the dose, sarin leads to acute respiratory failure and death. The mechanism(s) of sarin-induced respiratory failure is poorly understood. Sarin irreversibly inhibits acetylcholine esterase, leading to excessive synaptic levels of acetylcholine and, we have previously shown that sarin causes marked ventilatory changes including weakened response to hypoxia. We now show that LD50 sarin inhalation causes severe bronchoconstriction in rats, leading to airway resistance, increased hypoxia-induced factor-1α, and severe lung epithelium injury. Transferring animals into 60% oxygen chambers after sarin exposure improved the survival from about 50% to 75% at 24h; however, many animals died within hours after removal from the oxygen chambers. On the other hand, if LD50 sarin-exposed animals were administered the bronchodilator epinephrine, >90% of the animals survived. Moreover, while both epinephrine and oxygen treatments moderated cardiorespiratory parameters, the proinflammatory cytokine surge, and elevated expression of hypoxia-induced factor-1α, only epinephrine consistently reduced the sarin-induced bronchoconstriction. These data suggest that severe bronchoconstriction is a critical factor in the mortality induced by LD50 sarin inhalation, and epinephrine may limit the ventilatory, inflammatory, and lethal effects of sarin.

  12. In-airway molecular flow sensing: A new technology for continuous, noninvasive monitoring of oxygen consumption in critical care

    PubMed Central

    Ciaffoni, Luca; O’Neill, David P.; Couper, John H.; Ritchie, Grant A. D.; Hancock, Gus; Robbins, Peter A.

    2016-01-01

    There are no satisfactory methods for monitoring oxygen consumption in critical care. To address this, we adapted laser absorption spectroscopy to provide measurements of O2, CO2, and water vapor within the airway every 10 ms. The analyzer is integrated within a novel respiratory flow meter that is an order of magnitude more precise than other flow meters. Such precision, coupled with the accurate alignment of gas concentrations with respiratory flow, makes possible the determination of O2 consumption by direct integration over time of the product of O2 concentration and flow. The precision is illustrated by integrating the balance gas (N2 plus Ar) flow and showing that this exchange was near zero. Measured O2 consumption changed by <5% between air and O2 breathing. Clinical capability was illustrated by recording O2 consumption during an aortic aneurysm repair. This device now makes easy, accurate, and noninvasive measurement of O2 consumption for intubated patients in critical care possible. PMID:27532048

  13. Use of a dual lumen cannula for venovenous extra corporeal membrane oxygenation in a patient with acute respiratory distress syndrome and a previously inserted inferior vena cava filter: a case report

    PubMed Central

    Palizas Jr., Fernando; García, Christian Casabella; Norese, Mariano

    2016-01-01

    Extracorporeal membrane oxygenation is used in refractory hypoxemia in many clinical settings. Thoracic trauma patients usually develop acute respiratory distress syndrome. Due to high risk of bleeding, thrombotic complications present in this context are particularly difficult to manage and usually require insertion of an inferior vena cava filter to prevent embolism from the distal veins to the pulmonary circulation. Here, we present a case of a thoracic trauma patient with severe acute respiratory distress syndrome requiring venovenous extracorporeal membrane oxygenation via a right internal jugular double lumen cannula due to a previously inserted inferior vena cava filter caused by distal bilateral calf muscle vein deep vein thrombosis. PMID:27096680

  14. Oxygen sensing by primary cardiac fibroblasts: a key role of p21(Waf1/Cip1/Sdi1).

    PubMed

    Roy, Sashwati; Khanna, Savita; Bickerstaff, Alice A; Subramanian, Sukanya V; Atalay, Mustafa; Bierl, Michael; Pendyala, Srikanth; Levy, Dana; Sharma, Nidhi; Venojarvi, Mika; Strauch, Arthur; Orosz, Charles G; Sen, Chandan K

    2003-02-21

    In mammalian organs under normoxic conditions, O2 concentration ranges from 12% to <0.5%, with O2 approximately 14% in arterial blood and <10% in the myocardium. During mild hypoxia, myocardial O2 drops to approximately 1% to 3% or lower. In response to chronic moderate hypoxia, cells adjust their normoxia set point such that reoxygenation-dependent relative elevation of PO2 results in perceived hyperoxia. We hypothesized that O2, even in marginal relative excess of the PO2 to which cardiac cells are adjusted, results in activation of specific signal transduction pathways that alter the phenotype and function of these cells. To test this hypothesis, cardiac fibroblasts (CFs) isolated from adult murine ventricle were cultured in 10% or 21% O2 (hyperoxia relative to the PO2 to which cells are adjusted in vivo) and were compared with those cultured in 3% O2 (mild hypoxia). Compared with cells cultured in 3% O2, cells that were cultured in 10% or 21% O2 demonstrated remarkable reversible G2/M arrest and a phenotype indicative of differentiation to myofibroblasts. These effects were independent of NADPH oxidase function. CFs exposed to high O2 exhibited higher levels of reactive oxygen species production. The molecular signature response to perceived hyperoxia included (1) induction of p21, cyclin D1, cyclin D2, cyclin G1, Fos-related antigen-2, and transforming growth factor-beta1, (2) lowered telomerase activity, and (3) activation of transforming growth factor-beta1 and p38 mitogen-activated protein kinase. CFs deficient in p21 were resistant to such O2 sensitivity. This study raises the vital broad-based issue of controlling ambient O2 during the culture of primary cells isolated from organs.

  15. Bloodless reperfusion with the oxygen carrier HBOC-201 in acute myocardial infarction: a novel platform for cardioprotective probes delivery.

    PubMed

    García-Ruiz, Jose M; Galán-Arriola, Carlos; Fernández-Jiménez, Rodrigo; Aguero, Jaume; Sánchez-González, Javier; García-Alvarez, Ana; Nuno-Ayala, Mario; Dubé, Gregory P; Zafirelis, Zafiris; López-Martín, Gonzalo J; Bernal, Juan A; Lara-Pezzi, Enrique; Fuster, Valentín; Ibáñez, Borja

    2017-03-01

    Reperfusion, despite being required for myocardial salvage, is associated with additional injury. We hypothesize that infarct size (IS) will be reduced by a period of bloodless reperfusion with hemoglobin-based oxygen carriers (HBOC) before blood-flow restoration. In the pig model, we first characterized the impact of intracoronary perfusion with a fixed volume (600 ml) of a pre-oxygenated acellular HBOC, HBOC-201, on the healthy myocardium. HBOC-201 was administered through the lumen of the angioplasty balloon (i.e., distal to the occlusion site) immediately after onset of coronary occlusion at 1, 0.7, 0.4, or 0.2 ml/kg/min for 12, 17, 30, and 60 min, respectively, followed by blood-flow restoration. Outcome measures were systemic hemodynamics and LV performance assessed by the state-of-the-art cardiac magnetic resonance (CMR) imaging. The best performing HBOC-201 perfusion strategies were then tested for their impact on LV performance during myocardial infarction, in pigs subjected to 45 min mid-left anterior descending (LAD) coronary occlusion. At the end of the ischemia duration, pigs were randomized to regular reperfusion (blood-only reperfusion) vs. bloodless reperfusion (perfusion with pre-oxygenated HBOC-201 distal to the occlusion site), followed by blood-flow restoration. Hemodynamics and CMR-measured LV performance were assessed at 7- and 45-day follow-up. In modifications of the HBOC-201 procedure, glucose and insulin were included to support cardiac metabolism. A total of 66 pigs were included in this study. Twenty healthy pigs (5 per infusion protocol) were used in the study of healthy myocardium. Intracoronary administration of HBOC-201 (600 ml) at varying rates, including a flow of 0.4 ml/kg/min (corresponding to a maximum perfusion time of 30 min), did not damage the healthy myocardium. Slower perfusion (longer infusion time) was associated with permanent LV dysfunction and myocardial necrosis. A total of 46 pigs underwent MI induction

  16. An Oxygen-Sensing Two-Component System in the Burkholderia cepacia Complex Regulates Biofilm, Intracellular Invasion, and Pathogenicity.

    PubMed

    Schaefers, Matthew M; Liao, Tiffany L; Boisvert, Nicole M; Roux, Damien; Yoder-Himes, Deborah; Priebe, Gregory P

    2017-01-01

    Burkholderia dolosa is a member of the Burkholderia cepacia complex (BCC), which is a group of bacteria that cause chronic lung infection in patients with cystic fibrosis (CF) and can be associated with outbreaks carrying high morbidity and mortality. While investigating the genomic diversity of B. dolosa strains collected from an outbreak among CF patients, we previously identified fixL as a gene showing signs of strong positive selection. This gene has homology to fixL of the rhizobial FixL/FixJ two-component system. The goals of this study were to determine the functions of FixLJ and their role in virulence in B. dolosa. We generated a fixLJ deletion mutant and complemented controls in B. dolosa strain AU0158. Using a fixK-lacZ reporter we found that FixLJ was activated in low oxygen in multiple BCC species. In a murine pneumonia model, the B. dolosa fixLJ deletion mutant was cleared faster from the lungs and spleen than wild-type B. dolosa strain AU0158 at 7 days post infection. Interestingly, the fixLJ deletion mutant made more biofilm, albeit with altered structure, but was less motile than strain AU0158. Using RNA-seq with in vitro grown bacteria, we found ~11% of the genome was differentially expressed in the fixLJ deletion mutant relative to strain AU0158. Multiple flagella-associated genes were down-regulated in the fixLJ deletion mutant, so we also evaluated virulence of a fliC deletion mutant, which lacks a flagellum. We saw no difference in the ability of the fliC deletion mutant to persist in the murine model relative to strain AU0158, suggesting factors other than flagella caused the phenotype of decreased persistence. We found the fixLJ deletion mutant to be less invasive in human lung epithelial and macrophage-like cells. In conclusion, B. dolosa fixLJ is a global regulator that controls biofilm formation, motility, intracellular invasion/persistence, and virulence.

  17. An Oxygen-Sensing Two-Component System in the Burkholderia cepacia Complex Regulates Biofilm, Intracellular Invasion, and Pathogenicity

    PubMed Central

    Liao, Tiffany L.; Boisvert, Nicole M.; Priebe, Gregory P.

    2017-01-01

    Burkholderia dolosa is a member of the Burkholderia cepacia complex (BCC), which is a group of bacteria that cause chronic lung infection in patients with cystic fibrosis (CF) and can be associated with outbreaks carrying high morbidity and mortality. While investigating the genomic diversity of B. dolosa strains collected from an outbreak among CF patients, we previously identified fixL as a gene showing signs of strong positive selection. This gene has homology to fixL of the rhizobial FixL/FixJ two-component system. The goals of this study were to determine the functions of FixLJ and their role in virulence in B. dolosa. We generated a fixLJ deletion mutant and complemented controls in B. dolosa strain AU0158. Using a fixK-lacZ reporter we found that FixLJ was activated in low oxygen in multiple BCC species. In a murine pneumonia model, the B. dolosa fixLJ deletion mutant was cleared faster from the lungs and spleen than wild-type B. dolosa strain AU0158 at 7 days post infection. Interestingly, the fixLJ deletion mutant made more biofilm, albeit with altered structure, but was less motile than strain AU0158. Using RNA-seq with in vitro grown bacteria, we found ~11% of the genome was differentially expressed in the fixLJ deletion mutant relative to strain AU0158. Multiple flagella-associated genes were down-regulated in the fixLJ deletion mutant, so we also evaluated virulence of a fliC deletion mutant, which lacks a flagellum. We saw no difference in the ability of the fliC deletion mutant to persist in the murine model relative to strain AU0158, suggesting factors other than flagella caused the phenotype of decreased persistence. We found the fixLJ deletion mutant to be less invasive in human lung epithelial and macrophage-like cells. In conclusion, B. dolosa fixLJ is a global regulator that controls biofilm formation, motility, intracellular invasion/persistence, and virulence. PMID:28046077

  18. Polarimetric remote sensing in oxygen A and B bands: sensitivity study and information content analysis for vertical profile of aerosols

    NASA Astrophysics Data System (ADS)

    Ding, Shouguo; Wang, Jun; Xu, Xiaoguang

    2016-05-01

    Theoretical analysis is conducted to reveal the information content of aerosol vertical profile in space-borne measurements of the backscattered radiance and degree of linear polarization (DOLP) in oxygen (O2) A and B bands. Assuming a quasi-Gaussian shape for aerosol vertical profile characterized by peak height H and half width γ (at half maximum), the Unified Linearized Vector Radiative Transfer Model (UNL-VRTM) is used to simulate the Stokes four-vector elements of upwelling radiation at the top of atmosphere (TOA) and their Jacobians with respect to H and γ. Calculations for different aerosol types and different combinations of H and γ values show that the wide range of gas absorption optical depth in O2 A and B band enables the sensitivity of backscattered DOLP and radiance at TOA to the aerosol layer at different altitudes. Quantitatively, DOLP in O2 A and B bands is found to be more sensitive to H and γ than radiance, especially over the bright surfaces (with large visible reflectance). In many O2 absorption wavelengths, the degree of freedom of signal (DFS) for retrieving H (or γ) generally increases with H (and γ) and can be close to unity in many cases, assuming that the composite uncertainty from surface and aerosol scattering properties as well as measurements is less than 5 %. Further analysis demonstrates that DFS needed for simultaneous retrieval of H and γ can be obtained from a combined use of DOLP measurements at ˜ 10-100 O2 A and B absorption wavelengths (or channels), depending on the specific values of H. The higher the aerosol layer, the fewer number of channels for DOLP measurements in O2 A and B bands are needed for characterizing H and γ. Future hyperspectral measurements of DOLP in O2 A and B bands are needed to continue studying their potential and their combination with radiance and DOLP in atmospheric window channels for retrieving the vertical profiles of aerosols, especially highly scattering aerosols, over land.

  19. Severe Acute Cardiopulmonary Failure Related to Gadobutrol Magnetic Resonance Imaging Contrast Reaction: Successful Resuscitation With Extracorporeal Membrane Oxygenation.

    PubMed

    Guru, Pramod K; Bohman, J Kyle; Fleming, Chad J; Tan, Hon L; Sanghavi, Devang K; De Moraes, Alice Gallo; Barsness, Gregory W; Wittwer, Erica D; King, Bernard F; Arteaga, Grace M; Flick, Randall; Schears, Gregory J

    2016-03-01

    Nonanaphylactic noncardiogenic pulmonary edema leading to cardiorespiratory arrest related to the magnetic resonance imaging contrast agent gadobutrol has rarely been reported in the literature. Rarer is the association of hypokalemia with acidosis. We report 2 patients who had severe pulmonary edema associated with the use of gadobutrol contrast in the absence of other inciting agents or events. These cases were unique not only for their rare and severe presentations but also because they exemplified the increasing role of extracorporeal membrane oxygenation in resuscitation. Emergency extracorporeal membrane oxygenation resuscitation can be rapidly initiated and successful in the setting of a well-organized workflow, and it is a viable alternative and helps improve patient outcome in cases refractory to conventional resuscitative measures.

  20. Effect of the Pulsatile Extracorporeal Membrane Oxygenation on Hemodynamic Energy and Systemic Microcirculation in a Piglet Model of Acute Cardiac Failure.

    PubMed

    Itoh, Hideshi; Ichiba, Shingo; Ujike, Yoshihito; Douguchi, Takuma; Obata, Hideaki; Inamori, Syuji; Iwasaki, Tatsuo; Kasahara, Shingo; Sano, Shunji; Ündar, Akif

    2016-01-01

    The objective of this study was to compare the effects of pulsatile and nonpulsatile extracorporeal membrane oxygenation (ECMO) on hemodynamic energy and systemic microcirculation in an acute cardiac failure model in piglets. Fourteen piglets with a mean body weight of 6.08 ± 0.86 kg were divided into pulsatile (N = 7) and nonpulsatile (N = 7) ECMO groups. The experimental ECMO circuit consisted of a centrifugal pump, a membrane oxygenator, and a pneumatic pulsatile flow generator system developed in-house. Nonpulsatile ECMO was initiated at a flow rate of 140 mL/kg/min for the first 30 min with normal heart beating, with rectal temperature maintained at 36°C. Ventricular fibrillation was then induced with a 3.5-V alternating current to generate a cardiac dysfunction model. Using this model, we collected the data on pulsatile and nonpulsatile groups. The piglets were weaned off ECMO at the end of the experiment (180 min after ECMO was initiated). The animals did not receive blood transfusions, inotropic drugs, or vasoactive drugs. Blood samples were collected to measure hemoglobin, methemoglobin, blood gases, electrolytes, and lactic acid levels. Hemodynamic energy was calculated using the Shepard's energy equivalent pressure. Near-infrared spectroscopy was used to monitor brain and kidney perfusion. The pulsatile ECMO group had a higher atrial pressure (systolic and mean), and significantly higher regional saturation at the brain level, than the nonpulsatile group (for both, P < 0.05). Additionally, the pulsatile ECMO group had higher methemoglobin levels within the normal range than the nonpulsatile group. Our study demonstrated that pulsatile ECMO produces significantly higher hemodynamic energy and improves systemic microcirculation, compared with nonpulsatile ECMO in acute cardiac failure.

  1. Intravenous Immunoglobulin Prevents Murine Antibody-Mediated Acute Lung Injury at the Level of Neutrophil Reactive Oxygen Species (ROS) Production

    PubMed Central

    Semple, John W.; Kim, Michael; Hou, Jing; McVey, Mark; Lee, Young Jin; Tabuchi, Arata; Kuebler, Wolfgang M.; Chai, Zhong-Wei; Lazarus, Alan H.

    2012-01-01

    Transfusion-related acute lung injury (TRALI) is a leading cause of transfusion-associated mortality that can occur with any type of transfusion and is thought to be primarily due to donor antibodies activating pulmonary neutrophils in recipients. Recently, a large prospective case controlled clinical study of cardiac surgery patients demonstrated that despite implementation of male donors, a high incidence of TRALI still occurred and suggested a need for additional interventions in susceptible patient populations. To examine if intravenous immunoglobulin (IVIg) may be effective, a murine model of antibody-mediated acute lung injury that approximates human TRALI was examined. When BALB/c mice were injected with the anti-major histocompatibility complex class I antibody 34-1-2s, mild shock (reduced rectal temperature) and respiratory distress (dyspnea) were observed and pre-treatment of the mice with 2 g/kg IVIg completely prevented these symptoms. To determine IVIg's usefulness to affect severe lung damage, SCID mice, previously shown to be hypersensitive to 34-1-2s were used. SCID mice treated with 34-1-2s underwent severe shock, lung damage (increased wet/dry ratios) and 40% mortality within 2 hours. Treatment with 2 g/kg IVIg 18 hours before 34-1-2s administration completely protected the mice from all adverse events. Treatment with IVIg after symptoms began also reduced lung damage and mortality. While the prophylactic IVIg administration did not affect 34-1-2s-induced pulmonary neutrophil accumulation, bone marrow-derived neutrophils from the IVIg-treated mice displayed no spontaneous ROS production nor could they be stimulated in vitro with fMLP or 34-1-2s. These results suggest that IVIg prevents murine antibody-mediated acute lung injury at the level of neutrophil ROS production and thus, alleviating tissue damage. PMID:22363629

  2. Acute ascorbic acid ingestion increases skeletal muscle blood flow and oxygen consumption via local vasodilation during graded handgrip exercise in older adults.

    PubMed

    Richards, Jennifer C; Crecelius, Anne R; Larson, Dennis G; Dinenno, Frank A

    2015-07-15

    Human aging is associated with reduced skeletal muscle perfusion during exercise, which may be a result of impaired endothelium-dependent dilation and/or attenuated ability to blunt sympathetically mediated vasoconstriction. Intra-arterial infusion of ascorbic acid (AA) increases nitric oxide-mediated vasodilation and forearm blood flow (FBF) during handgrip exercise in older adults, yet it remains unknown whether an acute oral dose can similarly improve FBF or enhance the ability to blunt sympathetic vasoconstriction during exercise. We hypothesized that 1) acute oral AA would improve FBF (Doppler ultrasound) and oxygen consumption (V̇o2) via local vasodilation during graded rhythmic handgrip exercise in older adults (protocol 1), and 2) AA ingestion would not enhance sympatholysis in older adults during handgrip exercise (protocol 2). In protocol 1 (n = 8; 65 ± 3 yr), AA did not influence FBF or V̇o2 during rest or 5% maximal voluntary contraction (MVC) exercise, but increased FBF (199 ± 13 vs. 248 ± 16 ml/min and 343 ± 24 vs. 403 ± 33 ml/min; P < 0.05) and V̇o2 (26 ± 2 vs. 34 ± 3 ml/min and 43 ± 4 vs. 50 ± 5 ml/min; P < 0.05) at both 15 and 25% MVC, respectively. The increased FBF was due to elevations in forearm vascular conductance (FVC). In protocol 2 (n = 10; 63 ± 2 yr), following AA, FBF was similarly elevated during 15% MVC (∼ 20%); however, vasoconstriction to reflex increases in sympathetic activity during -40 mmHg lower-body negative pressure at rest (ΔFVC: -16 ± 3 vs. -16 ± 2%) or during 15% MVC (ΔFVC: -12 ± 2 vs. -11 ± 4%) was unchanged. Our collective results indicate that acute oral ingestion of AA improves muscle blood flow and V̇o2 during exercise in older adults via local vasodilation.

  3. Therapeutic targeting of oxygen-sensing prolyl hydroxylases abrogates ATF4-dependent neuronal death and improves outcomes after brain hemorrhage in several rodent models

    PubMed Central

    Karuppagounder, Saravanan S.; Alim, Ishraq; Khim, Soah J.; Bourassa, Megan W.; Sleiman, Sama F.; John, Roseleen; Thinnes, Cyrille C.; Yeh, Tzu-Lan; Demetriades, Marina; Neitemeier, Sandra; Cruz, Dana; Gazaryan, Irina; Killilea, David W.; Morgenstern, Lewis; Xi, Guohua; Keep, Richard F.; Schallert, Timothy; Tappero, Ryan V.; Zhong, Jian; Cho, Sunghee; Maxfield, Frederick R.; Holman, Theodore R.; Culmsee, Carsten; Fong, Guo-Hua; Su, Yijing; Ming, Guo-li; Song, Hongjun; Cave, John W.; Schofield, Christopher J.; Colbourne, Frederick; Coppola, Giovanni; Ratan, Rajiv R.

    2017-01-01

    Disability or death due to intracerebral hemorrhage (ICH) is attributed to blood lysis, liberation of iron, and consequent oxidative stress. Iron chelators bind to free iron and prevent neuronal death induced by oxidative stress and disability due to ICH, but the mechanisms for this effect remain unclear. We show that the hypoxia-inducible factor prolyl hydroxylase domain (HIF-PHD) family of iron-dependent, oxygen-sensing enzymes are effectors of iron chelation. Molecular reduction of the three HIF-PHD enzyme isoforms in the mouse striatum improved functional recovery after ICH. A low-molecular-weight hydroxyquinoline inhibitor of the HIF-PHD enzymes, adaptaquin, reduced neuronal death and behavioral deficits after ICH in several rodent models without affecting total iron or zinc distribution in the brain. Unexpectedly, protection from oxidative death in vitro or from ICH in vivo by adaptaquin was associated with suppression of activity of the prodeath factor ATF4 rather than activation of an HIF-dependent prosurvival pathway. Together, these findings demonstrate that brain-specific inactivation of the HIF-PHD metalloenzymes with the blood-brain barrier-permeable inhibitor adaptaquin can improve functional outcomes after ICH in several rodent models. PMID:26936506

  4. Therapeutic targeting of oxygen-sensing prolyl hydroxylases abrogates ATF4-dependent neuronal death and improves outcomes after brain hemorrhage in several rodent models

    DOE PAGES

    Karuppagounder, Saravanan S.; Alim, Ishraq; Khim, Soah J.; ...

    2016-03-02

    Disability or death due to intracerebral hemorrhage (ICH) is attributed to blood lysis, liberation of iron and consequent oxidative stress. Iron chelators bind to free iron and prevent neuronal death induced by oxidative stress and disability due to ICH, but the mechanisms for this effect remain unclear. Here we show that the hypoxia-inducible factor prolyl-hydroxylase (HIF- PHD) family of iron-dependent oxygen sensing enzymes are effectors of iron chelation. Molecular reduction of the three HIF-PHD enzyme isoforms in mouse striatum improved functional recovery following ICH. A low molecular weight hydroxyquinoline inhibitor of the HIF-PHDs, adaptaquin, reduced neuronal death and behavioral deficitsmore » following ICH in several rodent models without affecting total iron or zinc distribution in the brain. Unexpectedly, protection from oxidative death in vitro or from ICH in vivo by adaptaquin was associated with suppression of expression of the prodeath factor ATF4 rather than activation of a HIF-dependent prosurvival pathway. In conclusion, together these findings demonstrate that brain-specific inactivation of the HIF-PHD metalloenzymes with the blood-brain barrier permeable inhibitor adaptaquin can improve functional outcomes following ICH in multiple rodent species.« less

  5. Therapeutic targeting of oxygen-sensing prolyl hydroxylases abrogates ATF4-dependent neuronal death and improves outcomes after brain hemorrhage in several rodent models

    SciTech Connect

    Karuppagounder, Saravanan S.; Alim, Ishraq; Khim, Soah J.; Bourassa, Megan W.; Sleiman, Sama F.; John, Roseleen; Thinnes, Cyrille C.; Yeh, Tzu-Lan; Demetriades, Marina; Neitemeier, Sandra; Cruz, Dana; Gazaryan, Irina; Killilea, David W.; Morgenstern, Lewis; Xi, Guohu; Keep, Richard F.; Schallert, Timothy; Tappero, Ryan V.; Zhong, Jian; Cho, Sunghee; Maxfield, Frederick R.; Holman, T. R.; Culmsee, Carsten; Fong, Guo-Hua -H.; Su, Yijing; Ming, Guo-li; Song, Hongjun; Cave, John W.; Schofield, Christopher J.; Colbourne, Frederick; Coppola, Giovanni; Ratan, Rajiv R.

    2016-03-02

    Disability or death due to intracerebral hemorrhage (ICH) is attributed to blood lysis, liberation of iron and consequent oxidative stress. Iron chelators bind to free iron and prevent neuronal death induced by oxidative stress and disability due to ICH, but the mechanisms for this effect remain unclear. Here we show that the hypoxia-inducible factor prolyl-hydroxylase (HIF- PHD) family of iron-dependent oxygen sensing enzymes are effectors of iron chelation. Molecular reduction of the three HIF-PHD enzyme isoforms in mouse striatum improved functional recovery following ICH. A low molecular weight hydroxyquinoline inhibitor of the HIF-PHDs, adaptaquin, reduced neuronal death and behavioral deficits following ICH in several rodent models without affecting total iron or zinc distribution in the brain. Unexpectedly, protection from oxidative death in vitro or from ICH in vivo by adaptaquin was associated with suppression of expression of the prodeath factor ATF4 rather than activation of a HIF-dependent prosurvival pathway. In conclusion, together these findings demonstrate that brain-specific inactivation of the HIF-PHD metalloenzymes with the blood-brain barrier permeable inhibitor adaptaquin can improve functional outcomes following ICH in multiple rodent species.

  6. Phytoglobin: a novel nomenclature for plant globins accepted by the globin community at the 2014 XVIII conference on Oxygen-Binding and Sensing Proteins

    PubMed Central

    Hill, Robert; Hargrove, Mark; Arredondo-Peter, Raúl

    2016-01-01

    Hemoglobin (Hb) is a heme-containing protein found in the red blood cells of vertebrates. For many years, the only known Hb-like molecule in plants was leghemoglobin (Lb). The discovery that other Hb-like proteins existed in plants led to the term “nonsymbiotic Hbs (nsHbs)” to differentiate them from the Lbs. While this terminology was adequate in the early stages of research on the protein, the complexity of the research in this area necessitates a change in the definition of these proteins to delineate them from red blood cell Hb. At the 2014 XVIII Conference on Oxygen-Binding and Sensing Proteins, the group devoted to the study of heme-containing proteins, this issue was discussed and a consensus was reached on a proposed name change. We propose Phytoglobin (Phytogb) as a logical, descriptive name to describe a heme-containing (Hb-like) protein found in plants. It will be readily recognized by the research community without a prolonged explanation of the origin of the term. The classification system that has been established can essentially remain unchanged substituting Phytogb in place of nsHb. Here, we present a guide to the new nomenclature, with reference to the existing terminology and a phylogenetic scheme, placing the known Phytogbs in the new nomenclature. PMID:26998237

  7. Therapeutic targeting of oxygen-sensing prolyl hydroxylases abrogates ATF4-dependent neuronal death and improves outcomes after brain hemorrhage in several rodent models.

    PubMed

    Karuppagounder, Saravanan S; Alim, Ishraq; Khim, Soah J; Bourassa, Megan W; Sleiman, Sama F; John, Roseleen; Thinnes, Cyrille C; Yeh, Tzu-Lan; Demetriades, Marina; Neitemeier, Sandra; Cruz, Dana; Gazaryan, Irina; Killilea, David W; Morgenstern, Lewis; Xi, Guohua; Keep, Richard F; Schallert, Timothy; Tappero, Ryan V; Zhong, Jian; Cho, Sunghee; Maxfield, Frederick R; Holman, Theodore R; Culmsee, Carsten; Fong, Guo-Hua; Su, Yijing; Ming, Guo-li; Song, Hongjun; Cave, John W; Schofield, Christopher J; Colbourne, Frederick; Coppola, Giovanni; Ratan, Rajiv R

    2016-03-02

    Disability or death due to intracerebral hemorrhage (ICH) is attributed to blood lysis, liberation of iron, and consequent oxidative stress. Iron chelators bind to free iron and prevent neuronal death induced by oxidative stress and disability due to ICH, but the mechanisms for this effect remain unclear. We show that the hypoxia-inducible factor prolyl hydroxylase domain (HIF-PHD) family of iron-dependent, oxygen-sensing enzymes are effectors of iron chelation. Molecular reduction of the three HIF-PHD enzyme isoforms in the mouse striatum improved functional recovery after ICH. A low-molecular-weight hydroxyquinoline inhibitor of the HIF-PHD enzymes, adaptaquin, reduced neuronal death and behavioral deficits after ICH in several rodent models without affecting total iron or zinc distribution in the brain. Unexpectedly, protection from oxidative death in vitro or from ICH in vivo by adaptaquin was associated with suppression of activity of the prodeath factor ATF4 rather than activation of an HIF-dependent prosurvival pathway. Together, these findings demonstrate that brain-specific inactivation of the HIF-PHD metalloenzymes with the blood-brain barrier-permeable inhibitor adaptaquin can improve functional outcomes after ICH in several rodent models.

  8. Effects of pulmonary static inflation with 50% xenon on oxygen impairment during cardiopulmonary bypass for stanford type A acute aortic dissection

    PubMed Central

    Jin, Mu; Yang, Yanwei; Pan, Xudong; Lu, Jiakai; Zhang, Zhiquan; Cheng, Weiping

    2017-01-01

    Abstract Background: The goal of this study was to investigate the effects of pulmonary static inflation with 50% xenon on postoperative oxygen impairment during cardiopulmonary bypass (CPB) for Stanford type A acute aortic dissection (AAD). Methods: This prospective single-center nonrandomized controlled clinical trial included 100 adult patients undergoing surgery for Stanford type A AAD at an academic hospital in China. Fifty subjects underwent pulmonary static inflation with 50% oxygen from January 2013 to January 2014, and 50 underwent inflation with 50% xenon from January 2014 to December 2014. During CPB, the lungs were inflated with either 50% xenon (xenon group) or 50% oxygen (control group) to maintain an airway pressure of 5 cm H2O. The primary outcome was oxygenation index (OI) value after intubation, and 10 minutes and 6 hours after the operation. The second outcome was cytokine and reactive oxygen species levels after intubation and 10 minutes, 6 hours, and 24 hours after the operation. Results: Patients treated with xenon had lower OI levels compared to the control group before surgery (P = 0.002); however, there was no difference in postoperative values between the 2 groups. Following surgery, mean maximal OI values decreased by 18.8% and 33.8%, respectively, in the xenon and control groups. After surgery, the levels of interleukin-6 (IL-6), tumor necrosis factor alpha, and thromboxane B2 decreased by 23.5%, 9.1%, and 30.2%, respectively, in the xenon group, but increased by 10.8%, 26.2%, and 26.4%, respectively, in the control group. Moreover, IL-10 levels increased by 28% in the xenon group and decreased by 7.5% in the control group. There were significant time and treatment-time interaction effects on methane dicarboxylic aldehyde (P = 0.000 and P = 0.050, respectively) and myeloperoxidase (P = 0.000 and P = 0.001 in xenon and control groups, respectively). There was no difference in hospital mortality and 1-year

  9. Variations in Alveolar Partial Pressure for Carbon Dioxide and Oxygen Have Additive Not Synergistic Acute Effects on Human Pulmonary Vasoconstriction

    PubMed Central

    Croft, Quentin P. P.; Formenti, Federico; Talbot, Nick P.; Lunn, Daniel; Robbins, Peter A.; Dorrington, Keith L.

    2013-01-01

    The human pulmonary vasculature constricts in response to hypercapnia and hypoxia, with important consequences for homeostasis and adaptation. One function of these responses is to direct blood flow away from poorly-ventilated regions of the lung. In humans it is not known whether the stimuli of hypercapnia and hypoxia constrict the pulmonary blood vessels independently of each other or whether they act synergistically, such that the combination of hypercapnia and hypoxia is more effective than the sum of the responses to each stimulus on its own. We independently controlled the alveolar partial pressures of carbon dioxide (Paco2) and oxygen (Pao2) to examine their possible interaction on human pulmonary vasoconstriction. Nine volunteers each experienced sixteen possible combinations of four levels of Paco2 (+6, +1, −4 and −9 mmHg, relative to baseline) with four levels of Pao2 (175, 100, 75 and 50 mmHg). During each of these sixteen protocols Doppler echocardiography was used to evaluate cardiac output and systolic tricuspid pressure gradient, an index of pulmonary vasoconstriction. The degree of constriction varied linearly with both Paco2 and the calculated haemoglobin oxygen desaturation (1-So2). Mixed effects modelling delivered coefficients defining the interdependence of cardiac output, systolic tricuspid pressure gradient, ventilation, Paco2 and So2. No interaction was observed in the effects on pulmonary vasoconstriction of carbon dioxide and oxygen (p>0.64). Direct effects of the alveolar gases on systolic tricuspid pressure gradient greatly exceeded indirect effects arising from concurrent changes in cardiac output. PMID:23935847

  10. Acute short-term hyperoxia followed by mild hypoxia does not increase EPO production: resolving the "normobaric oxygen paradox".

    PubMed

    Debevec, Tadej; Keramidas, Michail E; Norman, Barbara; Gustafsson, Thomas; Eiken, Ola; Mekjavic, Igor B

    2012-03-01

    Recent findings suggest that besides renal tissue hypoxia, relative decrements in tissue oxygenation, using a transition of the breathing mixture from hyperoxic to normoxic, can also stimulate erythropoietin (EPO) production. To further clarify the importance of the relative change in tissue oxygenation on plasma EPO concentration [EPO], we investigated the effect of a consecutive hyperoxic and hypoxic breathing intervention. Eighteen healthy male subjects were assigned to either IHH (N = 10) or CON (N = 8) group. The IHH group breathed pure oxygen (F(i)O(2) ~ 1.0) for 1 h, followed by a 1-h period of breathing a hypoxic gas mixture (F(i)O(2) ~ 0.15). The CON group breathed a normoxic gas mixture (F(i)O(2) ~ 0.21) for the same duration (2 h). Blood samples were taken just before, after 60 min, and immediately after the 2-h exposure period. Thereafter, samples were taken at 3, 5, 8, 24, 32, and 48 h after the exposure. During the breathing interventions, subjects remained in supine position. There were significant increases in absolute [EPO] within groups at 8 and 32 h in the CON and at 32 h only in the IHH group. No significant differences in absolute [EPO] were observed between groups following the intervention. Relative (∆[EPO]) levels were significantly lower in the IHH than in the CON group, 5 and 8 h following exposure. The tested protocol of consecutive hyperoxic-hypoxic gas mixture breathing did not induce [EPO] synthesis stimulation. Moreover, the transient attenuation in ∆[EPO] in the IHH group was most likely due to a hyperoxic suppression. Hence, our findings provide further evidence against the "normobaric O(2) paradox" theory.

  11. Quadratic function between arterial partial oxygen pressure and mortality risk in sepsis patients: an interaction with simplified acute physiology score

    PubMed Central

    Zhang, Zhongheng; Ji, Xuqing

    2016-01-01

    Oxygen therapy is widely used in emergency and critical care settings, while there is little evidence on its real therapeutic effect. The study aimed to explore the impact of arterial oxygen partial pressure (PaO2) on clinical outcomes in patients with sepsis. A large clinical database was employed for the study. Subjects meeting the diagnostic criteria of sepsis were eligible for the study. All measurements of PaO2 were extracted. The primary endpoint was death from any causes during hospital stay. Survey data analysis was performed by using individual ICU admission as the primary sampling unit. Quadratic function was assumed for PaO2 and its interaction with other covariates were explored. A total of 199,125 PaO2 samples were identified for 11,002 ICU admissions. Each ICU stay comprised 18 PaO2 samples in average. The fitted multivariable model supported our hypothesis that the effect of PaO2 on mortality risk was in quadratic form. There was significant interaction between PaO2 and SAPS-I (p = 0.007). Furthermore, the main effect of PaO2 on SOFA score was nonlinear. The study shows that the effect of PaO2 on mortality risk is in quadratic function form, and there is significant interaction between PaO2 and severity of illness. PMID:27734905

  12. Quadratic function between arterial partial oxygen pressure and mortality risk in sepsis patients: an interaction with simplified acute physiology score.

    PubMed

    Zhang, Zhongheng; Ji, Xuqing

    2016-10-13

    Oxygen therapy is widely used in emergency and critical care settings, while there is little evidence on its real therapeutic effect. The study aimed to explore the impact of arterial oxygen partial pressure (PaO2) on clinical outcomes in patients with sepsis. A large clinical database was employed for the study. Subjects meeting the diagnostic criteria of sepsis were eligible for the study. All measurements of PaO2 were extracted. The primary endpoint was death from any causes during hospital stay. Survey data analysis was performed by using individual ICU admission as the primary sampling unit. Quadratic function was assumed for PaO2 and its interaction with other covariates were explored. A total of 199,125 PaO2 samples were identified for 11,002 ICU admissions. Each ICU stay comprised 18 PaO2 samples in average. The fitted multivariable model supported our hypothesis that the effect of PaO2 on mortality risk was in quadratic form. There was significant interaction between PaO2 and SAPS-I (p = 0.007). Furthermore, the main effect of PaO2 on SOFA score was nonlinear. The study shows that the effect of PaO2 on mortality risk is in quadratic function form, and there is significant interaction between PaO2 and severity of illness.

  13. Effect of setting high APRV guided by expiratory inflection point of pressure-volume curve on oxygen delivery in canine models of severe acute respiratory distress syndrome

    PubMed Central

    Li, Jia-Qiong; Xu, Hong-Yang; Li, Mao-Qin; Chen, Jing-Yu

    2016-01-01

    In the present study, the effect of setting high airway pressure release ventilation (APRV) pressure guided by an expiratory inflection point of pressure-volume (PV) curve following lung recruitment maneuver (RM) on oxygen delivery (DO2) in canine models of severe acute respiratory distress syndrome (ARDS) was examined. Canine models of severe ARDS were established by intravenous injection of oleic acid. After injection of sedative muscle relaxants, a PV curve plotted using the super-syringe technique, and the pressure at lower inflection point (LIP) at the inhale branch and the pressure at the point of maximum curvature (PMC) at the exhale branch were measured. The ventilation mode was biphasic positive airway pressure (BiPAP), an inspiration to expiration ratio of 1:2, and Phigh 40 cm H2O, Plow 25 cm H2O. Phigh was decreased to 30 cm H2O after 90 sec. The dogs were randomized into 3 groups after RM, i.e., Blip group, BiPAP Plow = LIP+2 cm H2O; Bpmc group, BiPAP Plow = PMC; and Apmc group. In the APRV group, Phigh was set as PMC, with an inspiratory duration of 4 sec and expiratory duration of 0.4 sec. PMC was 18±1.4 cm H2O, and LIP was 11±1.3 cm H2O. Thirty seconds after RM was stabilized, it was set as 0 h. Hemodynamics, oxygenation and DO2 were measured at 0, 1, 2 and 4 h after RM in ARDS dogs. The results demonstrated: i) cardiac index (CI) in the 3 groups, where CI was significantly decreased in the Bpmc group at 0, 1, 2 and 4 h after RM compared to prior to RM (P<0.05) as well as in the Blip and Apmc groups (P<0.05). CI in the Blip and Apmc groups was not significantly altered prior to and after RM. ii) Oxygenation at 0, 1, 2 and 4 h in the 3 groups was improved after RM and the oxygenation indices for the 3 groups at 1 and 2 h were not significantly different (P>0.05). However, the oxygenation index in the Blip group at 4 h was significantly lower than those at 0 h for the Apmc and Bpmc groups (P<0.05). Oxygenation for the Apmc group at 4 h was higher

  14. Variability in splanchnic tissue oxygenation during preterm red blood cell transfusion given for symptomatic anaemia may reveal a potential mechanism of transfusion-related acute gut injury

    PubMed Central

    Bailey, Sean M.; Hendricks-Muñoz, Karen D.; Mally, Pradeep V.

    2015-01-01

    Background There is increasing evidence indicating an association between red blood cell (RBC) transfusions and necrotising enterocolitis (NEC) in preterm infants, especially late-onset NEC. This phenomenon is referred to as transfusion-related acute gut injury (TRAGI). One theory as to a pathophysiological mechanism is that transfusion may result in an ischemia-reperfusion injury to intestinal tissue. We tested the hypothesis that there is significantly greater variability during transfusion in splanchnic tissue oxygen saturation (SrSO2) than in cerebral tissue oxygen saturation (CrSO2). Materials and methods This was a prospective, observational study using near-infrared spectroscopy to monitor SrSO2 and CrSO2 in preterm neonates undergoing RBC transfusion for symptomatic anaemia. Mean, standard deviation, highest and lowest SrSO2 and CrSO2 values during each transfusion were determined. The greatest difference in SrSO2 and CrSO2 during each transfusion was calculated, along with the coefficient of variation. Results We studied 37 subjects. Throughout all transfusions, the mean SrSO2 was 45.6% ±13.8 and the mean CrSO2 was 65.4% ±6.9 (p<0.001). The variability of SrSO2 was significantly greater than that of CrSO2. Averaging data from all subjects, the greatest difference in SrSO2 was 43.8% ±13.4 compared with 23.3% ±7.6 for CrSO2 (p<0.001). The mean coefficient of variation in all transfusions was 20.5% for SrSO2 and 6.0% for CrSO2 (p<0.001). Increasing post-conceptional age did not affect SrSO2 variability (R2 =0.022; p=0.379), whereas CrSO2 variability during transfusion decreased with increasing post-conceptional age (R2=0.209; p=0.004). Discussion In preterm infants, there is a large degree of tissue oxygenation variability in splanchnic tissue during RBC transfusion and this does not change with increasing maturity. We speculate that these findings, combined with lower average tissue oxygenation, may demonstrate susceptibility of the preterm gut to TRAGI

  15. Pseudomonas quinolone signalling system: a component of quorum sensing cascade is a crucial player in the acute urinary tract infection caused by Pseudomonas aeruginosa.

    PubMed

    Bala, Anju; Chhibber, Sanjay; Harjai, Kusum

    2014-11-01

    Pseudomonas aeruginosa is an opportunistic pathogen which employs quorum sensing system to regulate several genes required for its survival and pathogenicity within the host. Besides acylhomoserine lactone (AHL) mediated las and rhl systems, this organism possesses Pseudomonas quinolone signalling (PQS) system based on alkyl quinolone signal molecules. The quinolone system represents another layer of sophistication in the complex quorum sensing cascade. Therefore, in the present study, we evaluated the contribution of the PQS system in the establishment of acute urinary tract infection (UTI) in the mouse model. For this, wild-type parent strain of P. aeruginosa MPAO1 and its isogenic single transposon mutant strains pqsH and pqsA were employed to induce UTI in mice. PQS molecules in the tissue homogenates of mice were detected by high performance thin layer chromatography (HP-TLC) method. Virulence of strains was assessed in terms of bacteriological count, histopathological lesions in the renal and bladder tissue and generation of pathological index markers like reactive nitrogen intermediates and malondialdehyde. HP-TLC analysis showed presence of PQS molecules in the renal and bladder tissue of mice infected with MPAO1 while no PQS was detected in case of pqsH and pqsA mutant strains. Results indicated that MPAO1 possessing fully functional PQS biosynthetic genes was highly virulent and caused acute pyelonephritis with severe inflammation and tissue destruction. On the contrary, significant reduction in the log count, mild tissue damage and declined levels of pathological markers were observed in mice infected with mutant strains as compared to MPAO1. Further among mutants, all these parameters were maximally impaired in the pqsA mutant in which synthesis of alkyl quinolones was completely abolished due to the transposon mutation in respective gene. Virulence of the pqsH mutant strain was lesser than that of the MPAO1 but higher than pqsA mutant. In addition, the

  16. Detection of reactive oxygen species (ROS) by the oxidant-sensing probe 2',7'-dichlorodihydrofluorescein diacetate in the cyanobacterium Anabaena variabilis PCC 7937

    SciTech Connect

    Rastogi, Rajesh P.; Singh, Shailendra P.; Haeder, Donat-P.; Sinha, Rajeshwar P.

    2010-07-02

    The generation of reactive oxygen species (ROS) under simulated solar radiation (UV-B: 0.30 Wm{sup -2}, UV-A: 25.70 Wm{sup -2} and PAR: 118.06 Wm{sup -2}) was studied in the cyanobacterium Anabaena variabilis PCC 7937 using the oxidant-sensing fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). DCFH-DA is a nonpolar dye, converted into the polar derivative DCFH by cellular esterases that are nonfluorescent but switched to highly fluorescent DCF when oxidized by intracellular ROS and other peroxides. The images obtained from the fluorescence microscope after 12 h of irradiation showed green fluorescence from cells covered with 295, 320 or 395 nm cut-off filters, indicating the generation of ROS in all treatments. However, the green/red fluorescence ratio obtained from fluorescence microscopic analysis showed the highest generation of ROS after UV-B radiation in comparison to PAR or UV-A radiation. Production of ROS was also measured by a spectrofluorophotometer and results obtained supported the results of fluorescence microscopy. Low levels of ROS were detected at the start (0 h) of the experiment showing that they are generated even during normal metabolism. This study also showed that UV-B radiation causes the fragmentation of the cyanobacterial filaments which could be due to the observed oxidative stress. This is the first report for the detection of intracellular ROS in a cyanobacterium by fluorescence microscopy using DCFH-DA and thereby suggesting the applicability of this method in the study of in vivo generation of ROS.

  17. Effects of calcium-sensing receptors on apoptosis in rat hippocampus during hypoxia/re-oxygenation through the ERK1/2 pathway

    PubMed Central

    Wang, Peng; Wang, Li; Wang, Shilei; Li, Shuhong; Li, Yu; Zhang, Lin

    2015-01-01

    Objectives: To explore the effects of calcium-sensing receptors (CaSR) on apoptosis in rat hippocampus during hypoxia/re-oxygenation (H/R). Methods: After post-culturing of isolated rat hippocampus, the cultures were subjected to H/R, meanwhile gadolinium chloride (GdCl3, agonist of CaSR) and NPS 2390 (antagonists of CaSR) was added to reperfusion solution. The number of hippocampal neuron, cell proliferation assay and apoptosis rate was determined by inverted microscope, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and flow cytometer (FCM). Besides, caspase-3, Bax, cytochrome C (Cyt-c), extracellular signal-regulated protein kinase (ERK) 1/2, pERK1/2, P38 and pP38 were analyzed by western blotting. Results: The hippocampal neuron number and cell viability were significantly decreased after H/R treatment, and were further significantly reduced when co-treatment with CaSR agonist GdCl3. But the effects of GdCl3 were attenuated by NPS-2390. Whereas, apoptosis rate, the expression level of caspase-3, Bax and Cyt-c were all significantly increased under H/R condition, and was further significantly increased by GdCl3, but were reversed by NPS-2390 (P < 0.05). Moreover, there were no significant differences in expression of ERK1/2, P38 and pP38 among different groups. However, the expression of pERK1/2 was significantly increased after H/R treatment, but was significantly reduced by NPS 2390 (P < 0.05). Conclusion: The results suggest that CaSR might play significant roles in the induction of hippocampus apoptosis in rat during H/R through phosphorylation of ERK1/2. PMID:26550201

  18. Change in myocardial oxygen consumption employing continuous-flow LVAD with cardiac beat synchronizing system, in acute ischemic heart failure models.

    PubMed

    Umeki, Akihide; Nishimura, Takashi; Takewa, Yoshiaki; Ando, Masahiko; Arakawa, Mamoru; Kishimoto, Yuichiro; Tsukiya, Tomonori; Mizuno, Toshihide; Kyo, Shunei; Ono, Minoru; Taenaka, Yoshiyuki; Tatsumi, Eisuke

    2013-06-01

    Aiming the 'Bridge to Recovery' course, we have developed a novel left ventricular assist device (LVAD) controlling system. It can change the rotational speed of the continuous flow LVAD, EVAHEART, synchronized with the cardiac beat. Employing this system, we have already demonstrated that myocardial oxygen consumption (MVO2), which is considered to be equivalent to native heart load, changes in the hearts of normal goats. Herein, we examined changes in goats with acute ischemic heart failure. We studied 14 goats (56.1 ± 6.9 kg) with acute ischemic heart failure due to coronary microsphere embolization. We installed the EVAHEART and drive in four modes: "circuit-clamp", "continuous support", "counter-pulse", and "co-pulse", with 50 and 100 % bypass. In comparison to the circuit-clamp mode, MVO2 was reduced to 70.4 ± 17.9 % in the counter-pulse mode and increased to 90.3 ± 14.5 % in the co-pulse mode, whereas it was 80.0 ± 14.5 % in the continuous mode, with 100 % bypass (p < 0.05). The same difference was confirmed with 50 % bypass. This means that we may have a chance to change the native heart load by controlling the LVAD rotation in synchrony with the cardiac rhythm, so we named our controller as the Native Heart Load Control System (NHLCS). Employing changeable MVO2 with NHLCS according to the patient's condition may provide more opportunity for native heart recovery with LVAD, especially for patients with ischemic heart diseases.

  19. Combined application of dexamethasone and hyperbaric oxygen therapy yields better efficacy for patients with delayed encephalopathy after acute carbon monoxide poisoning

    PubMed Central

    Xiang, Wenping; Xue, Hui; Wang, Baojun; Li, Yuechun; Zhang, Jun; Jiang, Changchun; Liang, Furu; Pang, Jiangxia; Yu, Lehua

    2017-01-01

    Background Delayed encephalopathy after acute carbon monoxide (CO) poisoning (DEACMP) commonly occurs after recovering from acute CO poisoning. This study was performed to assess the efficacy of the combined application of dexamethasone and hyperbaric oxygen (HBO) therapy in patients with DEACMP. Patients and methods A total of 120 patients with DEACMP were recruited and randomly assigned into the experimental group (receiving dexamethasone 5 mg/day or 10 mg/day plus HBO therapy) and control group (HBO therapy as monotherapy). Meanwhile, the conventional treatments were provided for all the patients. We used the Mini-Mental State Examination (MMSE) scale to assess the cognitive function, the National Institutes of Health Stroke Scale (NIHSS) to assess the neurological function and the remission rate (RR) to assess the clinical efficacy. Myelin basic protein (MBP) in the cerebrospinal fluid (CSF) was also measured. Results After 4 weeks of treatment, compared to the control group, the experimental group had a significantly higher remission rate (P=0.032), a significantly higher average MMSE score (P=0.037) and a significantly lower average NIHSS score (P=0.002). Meanwhile, there was a trend toward better improvement with dexamethasone 10 mg/day, and the level of MBP in the CSF of patients was significantly lower in the experimental group than in the control group (P<0.0001). The addition of dexamethasone did not significantly increase the incidence of adverse events. Conclusion These results indicate that the combined application of dexamethasone and HBO therapy could yield better efficacy for patients with DEACMP and should be viewed as a potential new therapy. PMID:28260864

  20. Comparison of a New Miniaturized Extracorporeal Membrane Oxygenation System With Integrated Rotary Blood Pump to a Standard System in a Porcine Model of Acute Lung Injury.

    PubMed

    Pilarczyk, Kevin; Heckmann, Jens; Lyskawa, Kathrin; Strauß, Andreas; Haake, Nils; Wiese, Ingo; Jakob, Heinz; Kamler, Markus; Pizanis, Nikolaus

    2016-07-01

    Extracorporeal membrane oxygenation (ECMO) is used for severe acute respiratory distress syndrome. However, available ECMO systems are large and not well designed for fast delivery, emergency implantation, and interhospital transfer. Therefore, a new miniaturized oxygenator with integrated rotary blood pump (ILIAS) was developed and compared with a standard ECMO system in a large animal model. Acute lung injury was induced with repeated pulmonary saline lavage in 14 pigs until PaO2 /FiO2 -ratio was <100 mm Hg with a positive-end-expiratory-pressure of 5 mbar. Pigs were assigned to the following three groups: group 1 (n = 4): control group with conventional ventilation; group 2 (n = 5): standard vv-ECMO; group 3 (n = 5): vv-ILIAS. Gas exchange, hemodynamics, hemolysis, and coagulation activation were examined over a period of 8 h. No device failed during the observation period. PaCO2 decreased from 59.40 ± 4.14 mm Hg to 48.62 ± 4.50 mm Hg after 1 h in the ILIAS group compared with an improvement of PaCO2 from 48.86 ± 7.45 to 40.10 ± 6.02 in the conventional ECMO group (P = not significant [n.s.]). ARDS-induced respiratory acidosis was controlled promptly with a pH of 7.2 ± 0.1 at baseline increasing to 7.4 ± 0.1 in both study groups after 60 min of ECMO support. Mean carbon dioxide transfer was comparable between the conventional ECMO and ILIAS (211.36 ± 78.39 mL/min vs. 219.99 ± 76.72 mL/min, P = n.s.). PaO2 /FiO2 increased from 118.4 ± 15.5 mm Hg to 179.1 ± 72.4 mm Hg in the ILIAS group compared with an improvement of oxygenation from 107.1 ± 24.9 mm Hg to 179.0 ± 45.7 mm Hg in the standard ECMO group (P = n.s.). Mean oxygen transfer was calculated with 136.09 ± 30.25 mL/min for the ILIAS and 129.05 ± 36.28 mL/min for the standard ECMO. Hemodynamic instability or significant activation of the plasmatic coagulation was not

  1. Elevated Oxygen Consumption Rate in Response to Acute Low- Glucose Stress: Metformin Restores Rate to Normal Level

    PubMed Central

    Williams, Emmanuel D.; Rogers, Steven C.; Zhang, Xiaomin; Azhar, Gohar; Wei, Jeanne Y.

    2015-01-01

    Cardiovascular Disease (CVD) continues to be the leading cause of mortality among all age demographics in the United States, with the highest occurrence in populations aged 65 and older. Glucose levels, particularly hyperglycemia, are associated with the premature onset of age-related diseases including CVD. A major challenge in the treatment of elderly patients with chronically elevated blood glucose is the frequency of hypoglycemic episodes. Molecular mechanisms of hypoglycemia remain unclear, but are associated with premature onset of age-related-diseases. Here we report a mitochondrial metabolic profile assessing short-term (up to six hours) and longer-term (12–24 hours) durations of low-glucose stress. We observed that the antidiabetic biguanide and mitochondrial complex I inhibitor, metformin, can lower and restore the elevated oxygen consumption rate during shorter-term glucose stress to levels similar to that of cells cultured in normal glucose. This effect appears, in part, to involve activation of the 5′ AMP-activated protein kinase (AMPK). PMID:26256471

  2. No effect of acute beetroot juice ingestion on oxygen consumption, glucose kinetics, or skeletal muscle metabolism during submaximal exercise in males.

    PubMed

    Betteridge, Scott; Bescós, Raúl; Martorell, Miquel; Pons, Antoni; Garnham, Andrew P; Stathis, Christos C; McConell, Glenn K

    2016-02-15

    Beetroot juice, which is rich in nitrate (NO3 (-)), has been shown in some studies to decrease oxygen consumption (V̇o2) for a given exercise workload, i.e., increasing efficiency and exercise tolerance. Few studies have examined the effect of beetroot juice or nitrate supplementation on exercise metabolism. Eight healthy recreationally active males participated in three trials involving ingestion of either beetroot juice (Beet; ∼8 mmol NO3 (-)), Placebo (nitrate-depleted Beet), or Beet + mouthwash (Beet+MW), all of which were performed in a randomized single-blind crossover design. Two-and-a-half hours later, participants cycled for 60 min on an ergometer at 65% of V̇o2 peak. [6,6-(2)H]glucose was infused to determine glucose kinetics, blood samples obtained throughout exercise, and skeletal muscle biopsies that were obtained pre- and postexercise. Plasma nitrite [NO2 (-)] increased significantly (∼130%) with Beet, and this was attenuated in MW+Beet. Beet and Beet+MW had no significant effect on oxygen consumption, blood glucose, blood lactate, plasma nonesterified fatty acids, or plasma insulin during exercise. Beet and Beet+MW also had no significant effect on the increase in glucose disposal during exercise. In addition, Beet and Beet+MW had no significant effect on the decrease in muscle glycogen and phosphocreatine and the increase in muscle creatine, lactate, and phosphorylated acetyl CoA carboxylase during exercise. In conclusion, at the dose used, acute ingestion of beetroot juice had little effect on skeletal muscle metabolism during exercise.

  3. The acute effects of hemorrhagic shock on cerebral blood flow, brain tissue oxygen tension, and spreading depolarization following penetrating ballistic-like brain injury.

    PubMed

    Leung, Lai Yee; Wei, Guo; Shear, Deborah A; Tortella, Frank C

    2013-07-15

    Traumatic brain injury (TBI) often occurs in conjunction with additional trauma, resulting in secondary complications, such as hypotension as a result of blood loss. This study investigated the combined effects of penetrating ballistic-like brain injury (PBBI) and hemorrhagic shock (HS) on physiological parameters, including acute changes in regional cerebral blood flow (rCBF), brain tissue oxygen tension (P(bt)O₂), and cortical spreading depolarizations (CSDs). All recordings were initiated before injury (PBBI/HS/both) and maintained for 2.5 h. Results showed that PBBI alone and combined PBBI and HS produced a sustained impairment of ipsilateral rCBF that decreased by 70% from baseline (p<0.05). Significant and sustained reductions in P(bt)O₂ (50% baseline; p<0.05) were also observed in the injured hemisphere of the animals subjected to both PBBI and HS (PBBI+HS). In contrast, PBBI alone produced smaller, more transient reductions in P(bt)O₂ levels. The lower limit of cerebral autoregulation was significantly higher in the PBBI+HS group (p<0.05, compared to HS alone). Critically, combined injury resulted in twice the number of spontaneous CSDs as in PBBI alone (p<0.05). It also lowered the propagation speed of CSD and the threshold of CSD occurrence [induced CSD at higher mean arterial pressure (MAP)]. However, rCBF and P(bt)O₂ were not responsive to the depolarizations. Our data suggest that PBBI together with HS causes persistent impairment of CBF and brain tissue oxygen tension, increasing the probability of CSDs that likely contribute to secondary neuropathology and compromise neurological recovery.

  4. Plasma reactive oxygen metabolites and non-enzymatic antioxidant capacity are not affected by an acute increase of metabolic rate in zebra finches.

    PubMed

    Beamonte-Barrientos, Rene; Verhulst, Simon

    2013-07-01

    Understanding the sources of variation in oxidative stress level is a challenging issue due to the implications of oxidative stress for late age diseases, longevity and life-history trade-offs. Reactive oxygen species that cause oxidative stress are mostly a by-product of energy metabolism and it is therefore often assumed that oxidative stress is proportional to energy consumption. In mammals, an increased metabolic rate induced by cold exposure generally increases oxidative stress. However, compared to mammals, birds generate fewer free radicals per ATP produced and hence it is not obvious that, in birds, a cold-induced increase of metabolic rate increase oxidative stress. We tested whether cold-induced increase in metabolic rate increased oxidative stress in zebra finches by exposing individuals to cold and warm overnight temperatures. We registered metabolic rate and plasma levels of non-enzymatic antioxidants and reactive oxygen metabolites (ROMs), a measure of oxidative damage. Metabolic rate was on average 88 % higher in cold compared to warm temperature, with females being stronger affected than males. However, temperature had no effect on plasma antioxidants or our measure of oxidative damage. Middle-age birds had higher levels of plasma antioxidants than younger and older birds, but age was unrelated to ROMs. Birds showed repeatability of plasma ROMs across temperatures but not of non-enzymatic antioxidants. In contrast to similar studies in mammals, our results do not show evidence of increased oxidative stress in plasma after an acute cold-induced increase of metabolic rate but research in more bird species is needed to assess the generality of this pattern.

  5. Effect of automated red cell exchanges on oxygen saturation on-air, blood parameters and length of hospitalization in sickle cell disease patients with acute chest syndrome

    PubMed Central

    Aneke, John C.; Huntley, Nancy; Porter, John; Eleftheriou, Perla

    2016-01-01

    Background: Red cell exchanges (RCEs) lead to improvement in tissue oxygenation and reduction in inflammatory markers in sickle cell disease (SCD) patients who present with acute chest syndrome (ACS). The aim of this study is to evaluate the effects of automated-RCE (auto-RCE) on oxygen saturation (SpO2) on-air, blood counts, the time to correct the parameters and length of hospitalization after the exchange in SCD patients presenting with ACS. Subjects and Methods: This was 2 years study involving five SCD patients; the time for SpO2 on air to increase to ≥95% and chest symptoms to resolve, postprocedure, as well as the length of in-patient hospitalization was recorded. All data were entered into Statistical Package for Social Sciences Version 20.0 (SPSS Inc., Chicago, IL, USA) computer software for analyses. Results: The study involved 4 (80%) hemoglobin (Hb) SS and 1 (20%) HbSC patients. The median time of SpO2 recovery was 24 h, ranging from 6 to 96 h. About 60% (3/5) of patients achieved optimal SpO2 within 24 h post-RCE, while discharge from intensive care unit was 24 h after auto-RCE in one patient. The Hb concentration was significantly higher, while the total white cell and absolute neutrophil counts were significantly lower at the time of resolution of symptoms, compared to before auto-RCE (P < 0.05). The average post auto-red cell transfusion symptoms duration was 105.6 (24–240) h while mean inpatient stay was 244.8 (144–456) h. Conclusion: Auto-RCE could reverse hypoxia in ACS within 24 h. PMID:27397962

  6. Benzolamide improves oxygenation and reduces acute mountain sickness during a high-altitude trek and has fewer side effects than acetazolamide at sea level.

    PubMed

    Collier, David J; Wolff, Chris B; Hedges, Anne-Marie; Nathan, John; Flower, Rod J; Milledge, James S; Swenson, Erik R

    2016-06-01

    Acetazolamide is the standard carbonic anhydrase (CA) inhibitor used for acute mountain sickness (AMS), however some of its undesirable effects are related to intracellular penetrance into many tissues, including across the blood-brain barrier. Benzolamide is a much more hydrophilic inhibitor, which nonetheless retains a strong renal action to engender a metabolic acidosis and ventilatory stimulus that improves oxygenation at high altitude and reduces AMS. We tested the effectiveness of benzolamide versus placebo in a first field study of the drug as prophylaxis for AMS during an ascent to the Everest Base Camp (5340 m). In two other studies performed at sea level to test side effect differences between acetazolamide and benzolamide, we assessed physiological actions and psychomotor side effects of two doses of acetazolamide (250 and 1000 mg) in one group of healthy subjects and in another group compared acetazolamide (500 mg), benzolamide (200 mg) and lorazepam (2 mg) as an active comparator for central nervous system (CNS) effects. At high altitude, benzolamide-treated subjects maintained better arterial oxygenation at all altitudes (3-6% higher at all altitudes above 4200 m) than placebo-treated subjects and reduced AMS severity by roughly 50%. We found benzolamide had fewer side effects, some of which are symptoms of AMS, than any of the acetazolamide doses in Studies 1 and 2, but equal physiological effects on renal function. The psychomotor side effects of acetazolamide were dose dependent. We conclude that benzolamide is very effective for AMS prophylaxis. With its lesser CNS effects, benzolamide may be superior to acetazolamide, in part, because some of the side effects of acetazolamide may contribute to and be mistaken for AMS.

  7. Improved Oxygenation 24 Hours After Transition to Airway Pressure Release Ventilation or High-Frequency Oscillatory Ventilation Accurately Discriminates Survival in Immunocompromised Pediatric Patients With Acute Respiratory Distress Syndrome*

    PubMed Central

    Yehya, Nadir; Topjian, Alexis A.; Thomas, Neal J.; Friess, Stuart H.

    2014-01-01

    Objectives Children with an immunocompromised condition and requiring invasive mechanical ventilation have high risk of death. Such patients are commonly transitioned to rescue modes of non-conventional ventilation, including airway pressure release ventilation and high-frequency oscillatory ventilation, for acute respiratory distress syndrome refractory to conventional ventilation. Our aim was to describe our experience with airway pressure release ventilation and high-frequency oscillatory ventilation in children with an immunocompromised condition and acute respiratory distress syndrome refractory to conventional ventilation and to identify factors associated with survival. Design Retrospective cohort study. Setting Tertiary care, university-affiliated PICU. Patients Sixty pediatric patients with an immunocompromised condition and acute respiratory distress syndrome refractory to conventional ventilation transitioned to either airway pressure release ventilation or high-frequency oscillatory ventilation. Interventions None. Measurements and Main Results Demographic data, ventilator settings, arterial blood gases, oxygenation index, and Pao2/Fio2 were recorded before transition to either mode of nonconventional ventilation and at predetermined intervals after transition for up to 5 days. Mortality in the entire cohort was 63% and did not differ between patients transitioned to airway pressure release ventilation and high-frequency oscillatory ventilation. For both airway pressure release ventilation and high-frequency oscillatory ventilation, improvements in oxygenation index and Pao2/Fio2 at 24 hours expressed as a fraction of pretransition values (oxygenation index24/oxygenation indexpre and Pao2/Fio224/Pao2/FIO2pre) reliably discriminated nonsurvivors from survivors, with receiver operating characteristic areas under the curves between 0.89 and 0.95 (p for all curves < 0.001). Sensitivity-specificity analysis suggested that less than 15% reduction in

  8. Optimization of Positive End-Expiratory Pressure targeting the best arterial oxygen transport in the Acute Respiratory Distress Syndrome: the OPTIPEP study.

    PubMed

    Chimot, Loïc; Fedun, Yannick; Gacouin, Arnaud; Campillo, Boris; Marqué, Sophie; Gros, Antoine; Delour, Pierre; Bedon-Carte, Sandrine; Le Tulzo, Yves

    2016-12-13

    The optimal setting for positive end-expiratory pressure (PEEP) in mechanical ventilation remains controversial in the treatment of acute respiratory distress syndrome (ARDS). The aim of this study was to determine the optimum PEEP level in ARDS, which we defined as the level that allowed the best arterial oxygen delivery (DO2).We conducted a physiological multicenter prospective study on patients who suffering from ARDS according to standard definition and persistent after 6 hours of ventilation. The PEEP was set to 6 cmH2O at the beginning of the test and then was increased by 2 cmH2O after at least 15 min of being stabilized until the plateau pressure achieved 30 cmH2O. At each step, the cardiac output was measured by trans-esophageal echocardiography and gas blood was sampled.We were able to determine the optimal PEEP for twelve patients. The ratio of PaO2/FiO2 at inclusion was 131±40 with a mean FiO2 of 71±3%. The optimal PEEP level was lower than the higher PEEP despite a constant increase in SaO2. The optimal PEEP levels varied between 8 and 18 cmH2O.Our results show that in ARDS patients the optimal PEEP differs between each patient and require being determined with monitoring.

  9. Acute exposure to 930 MHz CW electromagnetic radiation in vitro affects reactive oxygen species level in rat lymphocytes treated by iron ions.

    PubMed

    Zmyślony, Marek; Politanski, Piotr; Rajkowska, Elzbieta; Szymczak, Wieslaw; Jajte, Jolanta

    2004-07-01

    The aim of this study was to test the hypothesis that the 930 MHz continuous wave (CW) electromagnetic field, which is the carrier of signals emitted by cellular phones, affects the reactive oxygen species (ROS) level in living cells. Rat lymphocytes were used in the experiments. A portion of the lymphocytes was treated with iron ions to induce oxidative processes. Exposures to electromagnetic radiation (power density 5 W/m2, theoretical calculated SAR = 1.5 W/kg) were performed within a GTEM cell. Intracellular ROS were measured by the fluorescent probe dichlorofluorescin diacetate (DCF-DA). The results show that acute (5 and 15 min) exposure does not affect the number of produced ROS. If, however, FeCl2 with final concentration 10 microg/ml was added to the lymphocyte suspensions to stimulate ROS production, after both durations of exposure, the magnitude of fluorescence (ROS level during the experiment) was significantly greater in the exposed lymphocytes. The character of the changes in the number of free radicals observed in our experiments was qualitatively compatible with the theoretical prediction from the model of electromagnetic radiation effect on radical pairs.

  10. Defective quorum sensing of acute lymphoblastic leukemic cells: evidence of collective behavior of leukemic populations as semi-autonomous aberrant ecosystems

    PubMed Central

    Patel, Sapan J; Dao, Su; Darie, Costel C; Clarkson, Bayard D

    2016-01-01

    Quorum sensing (QS) is a generic term used to describe cell-cell communication and collective decision making by bacterial and social insects to regulate the expression of specific genes in controlling cell density and other properties of the populations in response to nutrient supply or changes in the environment. QS mechanisms also have a role in higher organisms in maintaining homeostasis, regulation of the immune system and collective behavior of cancer cell populations. In the present study, we used a p190BCR-ABL driven pre-B acute lymphoblastic leukemia (ALL3) cell line derived from the pleural fluid of a terminally ill patient with ALL to test the QS hypothesis in leukemia. ALL3 cells don’t grow at low density (LD) in liquid media but grow progressively faster at increasingly high cell densities (HD) in contrast to other established leukemic cell lines that grow well at very low starting cell densities. The ALL3 cells at LD are poised to grow but shortly die without additional stimulation. Supernates of ALL3 cells (HDSN) and some other primary cells grown at HD stimulate the growth of the LD ALL3 cells without which they won’t survive. To get further insight into the activation processes we performed microarray analysis of the LD ALL3 cells after stimulation with ALL3 HDSN at days 1, 3, and 6. This screen identified several candidate genes, and we linked them to signaling networks and their functions. We observed that genes involved in lipid, cholesterol, fatty acid metabolism, and B cell activation are most up- or down-regulated upon stimulation of the LD ALL3 cells using HDSN. We also discuss other pathways that are differentially expressed upon stimulation of the LD ALL3 cells. Our findings suggest that the Ph+ ALL population achieves dominance by functioning as a collective aberrant ecosystem subject to defective quorum-sensing regulatory mechanisms. PMID:27429840

  11. Efficacy of N-Butylphthalide and Hyperbaric Oxygen Therapy on Cognitive Dysfunction in Patients with Delayed Encephalopathy After Acute Carbon Monoxide Poisoning

    PubMed Central

    Xiang, Wenping; Xue, Hui; Wang, Baojun; Li, Yuechun; Zhang, Jun; Jiang, Changchun; Pang, Jiangxia

    2017-01-01

    Background Delayed encephalopathy after acute carbon monoxide (CO) poisoning (DEACMP) is one of the most serious complications after CO poisoning. This study was conducted to explore the efficacy of the combined application of N-Butylphthalide and hyperbaric oxygenation therapy (HBO) on cognitive dysfunction in patients with DEACMP. Material/Methods A total of 184 patients with DEACMP were randomly assigned to either receive HBO or N-Butylphthalide and HBO. Meanwhile, all patients received conventional treatment. The total remission rate (RR) was used to assess the clinical efficacy. The Mini-Mental State Examination (MMSE) was used to assess the cognitive function, and the National Institutes of Health Stroke Scale (NIHSS) was used to assess the neurological function. Results Finally, there were 90 and 94 patients in the control and experimental groups, respectively. After eight weeks of treatment, the total RR in the experimental group (47.9%) was significantly higher than that in the control group (33.3%). Compared to the control group, significantly more patients in the experimental group had MMSE scores of 24–30. The lower NIHSS score in the experimental group showed that N-Butylphthalide had the effect of preservation and restoration of neurological function. No obvious drug toxicity or liver and kidney dysfunction was observed, and there was no significant change in the level of blood glucose and blood lipids. Conclusions These results indicated that the combined application of N-Butylphthalide and HBO could significantly improve the cognitive dysfunction of patients with DEACMP and have great clinical efficacy, which should be further studied. PMID:28352069

  12. S(p)O(2) values in acute medical admissions breathing air--implications for the British Thoracic Society guideline for emergency oxygen use in adult patients?

    PubMed

    Smith, Gary B; Prytherch, David R; Watson, Duncan; Forde, Val; Windsor, Alastair; Schmidt, Paul E; Featherstone, Peter I; Higgins, Bernie; Meredith, Paul

    2012-10-01

    S(p)O(2) is routinely used to assess the well-being of patients, but it is difficult to find an evidence-based description of its normal range. The British Thoracic Society (BTS) has published guidance for oxygen administration and recommends a target S(p)O(2) of 94-98% for most adult patients. These recommendations rely on consensus opinion and small studies using arterial blood gas measurements of saturation (S(a)O(2)). Using large datasets of routinely collected vital signs from four hospitals, we analysed the S(p)O(2) range of 37,593 acute general medical inpatients (males: 47%) observed to be breathing room air. Age at admission ranged from 16 to 105 years with a mean (SD) of 64 (21) years. 19,642 admissions (52%) were aged <70 years. S(p)O(2) ranged from 70% to 100% with a median (IQR) of 97% (95-98%). S(p)O(2) values for males and females were similar. In-hospital mortality for the study patients was 5.27% (range 4.80-6.27%). Mortality (95% CI) for patients with initial S(p)O(2) values of 97%, 96% and 95% was 3.65% (3.22-4.13); 4.47% (3.99-5.00); and 5.67% (5.03-6.38), respectively. Additional analyses of S(p)O(2) values for 37,299 medical admissions aged ≥18 years provided results that were distinctly different to those upon which the current BTS guidelines based their definition of normality. Our findings suggest that the BTS should consider changing its target saturation for actively treated patients not at risk of hypercapnic respiratory failure to 96-98%.

  13. Fucoidan inhibits proliferation of the SKM-1 acute myeloid leukaemia cell line via the activation of apoptotic pathways and production of reactive oxygen species.

    PubMed

    Wei, Chunmei; Xiao, Qing; Kuang, Xingyi; Zhang, Tao; Yang, Zesong; Wang, Li

    2015-11-01

    Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and a high risk of progression to acute myeloid leukaemia (AML). Fucoidan, a complex sulphated polysaccharide isolated from the cell wall of brown seaweeds, has recently attracted attention for its multiple biological activities and its potential as a novel candidate for cancer therapy. In the present study, the anti‑cancer activity of fucoidan was investigated in the MDS/AML cell line SKM‑1. Fucoidan inhibited proliferation, induced apoptosis and caused G1-phase arrest of the cell cycle in SKM‑1 cells as determined by a cell counting kit 8 assay and flow cytometry. Furthermore, reverse transcription quantitative polymerase chain reaction and western blot analyses indicated that treatment with fucoidan (100 µg/ml for 48 h) activated Fas and caspase‑8 in SKM‑1 cells, which are critical for the extrinsic apoptotic pathway; furthermore, caspase‑9 was activated via decreases in phosphoinositide-3 kinase/Akt signaling as indicated by reduced levels of phosphorylated Akt, suggesting the involvement of the intrinsic apoptotic pathway. In addition, fucoidan treatment of SKM‑1 cells resulted in the generation of reactive oxygen species (ROS) as determined by staining with dichloro-dihydro-fluorescein diacetate. These results suggested that the mechanisms of the anti‑cancer effects of fucoidan in SKM‑1 are closely associated with cell cycle arrest and apoptotic cell death, which partly attributed to the activation of apoptotic pathways and accumulation of intracellular ROS. Our results demonstrated that Fucoidan inhibits proliferation and induces the apoptosis of SKM‑1 cells, which provides substantial therapeutic potential for MDS treatment.

  14. Oxygen partial pressure sensor

    DOEpatents

    Dees, D.W.

    1994-09-06

    A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured. 1 fig.

  15. Oxygen partial pressure sensor

    DOEpatents

    Dees, Dennis W.

    1994-01-01

    A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured.

  16. Influence of in-plane and bridging oxygen vacancies of SnO2 nanostructures on CH4 sensing at low operating temperatures

    NASA Astrophysics Data System (ADS)

    Bonu, Venkataramana; Das, A.; Prasad, Arun K.; Krishna, Nanda Gopala; Dhara, Sandip; Tyagi, A. K.

    2014-12-01

    Role of "O" defects in sensing pollutant with nanostructured SnO2 is not well understood, especially at low temperatures. SnO2 nanoparticles were grown by soft chemistry route followed by subsequent annealing treatment under specific conditions. Nanowires were grown by chemical vapor deposition technique. A systematic photoluminescence (PL) investigation of "O" defects in SnO2 nanostructures revealed a strong correlation between shallow donors created by the in-plane and the bridging "O" vacancies and gas sensing at low temperatures. These SnO2 nanostructures detected methane (CH4), a reducing and green house gas at a low temperature of 50 °C. Response of CH4 was found to be strongly dependent on surface defect in comparison to surface to volume ratio. Control over "O" vacancies during the synthesis of SnO2 nanomaterials, as supported by X-ray photoelectron spectroscopy and subsequent elucidation for low temperature sensing are demonstrated.

  17. Perfluorododecanoic acid-induced steroidogenic inhibition is associated with steroidogenic acute regulatory protein and reactive oxygen species in cAMP-stimulated Leydig cells.

    PubMed

    Shi, Zhimin; Feng, Yixing; Wang, Jianshe; Zhang, Hongxia; Ding, Lina; Dai, Jiayin

    2010-04-01

    Perfluorododecanoic acid (PFDoA) can be detected in environmental matrices and human serum and has been shown to inhibit testicular steroidogenesis in rats. However, the mechanisms that are responsible for the toxic effects of PFDoA remain unknown. The aims of this study were to investigate the mechanism of steroidogenesis inhibition by PFDoA and to identify the molecular target of PFDoA in Leydig cells. The effects of PFDoA on steroid synthesis in Leydig cells were assessed by radioimmunoassay. The expression of key genes and proteins in steroid biosynthesis was determined by real-time PCR and Western blot analysis. Reactive oxygen species (ROS) and hydrogen peroxide (H(2)O(2)) levels were determined using bioluminescence assays. PFDoA inhibited adenosine 3',5'-cyclophosphate (cAMP)-stimulated steroidogenesis in mouse Leydig tumor cells (mLTC-1) and primary rat Leydig cells in a dose-dependent manner. However, PFDoA (1-100 microM) did not exhibit effects on cell viability and cellular ATP levels in mLTC-1 cells. PFDoA inhibited steroidogenic acute regulatory protein (StAR) promoter activity and StAR expression at the messenger RNA (mRNA) and protein levels but did not affect mRNA levels of peripheral-type benzodiazepine receptor, cholesterol side-chain cleavage enzyme, or 3beta-hydroxysteroid dehydrogenase in cAMP-stimulated mLTC-1 cells. PFDoA treatment also resulted in increased levels of mitochondrial ROS and H(2)O(2). After excessive ROS and H(2)O(2) were eliminated in PFDoA-treated mLTC-1 cells by MnTMPyP (a superoxide dismutase analog), progesterone production was partially restored and StAR mRNA and protein levels were partially recovered. These data show that PFDoA inhibits steroidogenesis in cAMP-stimulated Leydig cells by reducing the expression of StAR through a model of action involving oxidative stress.

  18. Resveratrol Sensitizes Acute Myelogenous Leukemia Cells to Histone Deacetylase Inhibitors through Reactive Oxygen Species-Mediated Activation of the Extrinsic Apoptotic PathwayS⃞

    PubMed Central

    Yaseen, Alae; Chen, Shuang; Hock, Stefanie; Rosato, Roberto; Dent, Paul; Dai, Yun

    2012-01-01

    Histone deacetylase inhibitors (HDACIs) activate the prosurvival nuclear factor-κB (NF-κB) pathway by hyperacetylating RelA/p65, whereas the chemopreventive agent resveratrol inhibits NF-κB by activating the class III histone deacetylase Sirt1. Interactions between resveratrol and pan-HDACIs (vorinostat and panobinostat) were examined in human acute myelogenous leukemia (AML) cells. Pharmacologically achievable resveratrol concentrations (25–50 μM) synergistically potentiated HDACI lethality in AML cell lines and primary AML blasts. Resveratrol antagonized RelA acetylation and NF-κB activation in HDACI-treated cells. However, short hairpin RNA Sirt1 knockdown failed to modify HDACI sensitivity, which suggests that factors other than or in addition to Sirt1 activation contribute to resveratrol/HDACI interactions. These interactions were associated with death receptor 5 (DR5) up-regulation and caspase-8 activation, whereas cells expressing dominant-negative caspase-8 were substantially protected from resveratrol/HDACI treatment, which suggests a significant functional role for the extrinsic apoptotic pathway in lethality. Exposure to resveratrol with HDACI induced sustained reactive oxygen species (ROS) generation, which was accompanied by increased levels of DNA double-strand breaks, as reflected in γH2A.X and comet assays. The free radical scavenger Mn(III)tetrakis(4-benzoic acid)porphyrin chloride blocked ROS generation, DR5 up-regulation, caspase-8 activation, DNA damage, and apoptosis, which indicates a primary role for oxidative injury in lethality. Analyses of cell-cycle progression and 5-ethynyl-2′-deoxyuridine incorporation through flow cytometry revealed that resveratrol induced S-phase accumulation; this effect was abrogated by HDACI coadministration, which suggests that cells undergoing DNA synthesis may be particularly vulnerable to HDACI lethality. Collectively, these findings indicate that resveratrol interacts synergistically with HDACIs in

  19. Normal Hematopoietic Progenitor Subsets Have Distinct Reactive Oxygen Species, BCL2 and Cell-Cycle Profiles That Are Decoupled from Maturation in Acute Myeloid Leukemia

    PubMed Central

    Hills, Robert K.; Knapper, Steve; Steadman, Lora; Qureshi, Ushna; Rector, Jerrald L.; Bradbury, Charlotte; Russell, Nigel H.; Vyas, Paresh; Burnett, Alan K.; Grimwade, David; Hole, Paul S.; Freeman, Sylvie D.

    2016-01-01

    In acute myeloid leukemia (AML) quiescence and low oxidative state, linked to BCL2 mitochondrial regulation, endow leukemic stem cells (LSC) with treatment-resistance. LSC in CD34+ and more mature CD34− AML have heterogeneous immunophenotypes overlapping with normal stem/progenitor cells (SPC) but may be differentiated by functional markers. We therefore investigated the oxidative/reactive oxygen species (ROS) profile, its relationship with cell-cycle/BCL2 for normal SPC, and whether altered in AML and myelodysplasia (MDS). In control BM (n = 24), ROS levels were highest in granulocyte-macrophage progenitors (GMP) and CD34− myeloid precursors but megakaryocyte-erythroid progenitors had equivalent levels to CD34+CD38low immature-SPC although they were ki67high. BCL2 upregulation was specific to GMPs. This profile was also observed for CD34+SPC in MDS-without-excess-blasts (MDS-noEB, n = 12). Erythroid CD34− precursors were, however, abnormally ROS-high in MDS-noEB, potentially linking oxidative stress to cell loss. In pre-treatment AML (n = 93) and MDS-with-excess-blasts (MDS-RAEB) (n = 14), immunophenotypic mature-SPC had similar ROS levels to co-existing immature-SPC. However ROS levels varied between AMLs; Flt3ITD+/NPM1wild-type CD34+SPC had higher ROS than NPM1mutated CD34+ or CD34− SPC. An aberrant ki67lowBCL2high immunophenotype was observed in CD34+AML (most prominent in Flt3ITD AMLs) but also in CD34− AMLs and MDS-RAEB, suggesting a shared redox/pro-survival adaptation. Some patients had BCL2 overexpression in CD34+ ROS-high as well as ROS-low fractions which may be indicative of poor early response to standard chemotherapy. Thus normal SPC subsets have distinct ROS, cell-cycle, BCL2 profiles that in AML /MDS-RAEB are decoupled from maturation. The combined profile of these functional properties in AML subpopulations may be relevant to differential treatment resistance. PMID:27669008

  20. Effect of annealing in a various oxygen atmosphere on structural, optical, electrical and gas sensing properties of MoxOy thin films

    NASA Astrophysics Data System (ADS)

    Arfaoui, A.; Ouni, B.; Touihri, S.; Mhamdi, A.; Labidi, A.; Manoubi, T.

    2015-07-01

    Molybdenum oxide thin films were thermally evaporated on a glass substrate and monitored by an annealing process in a variable oxygen atmosphere. The effects of post annealing condition on the microstructural, morphological, optical and electrical properties were investigated using X-ray diffraction, Raman spectroscopy, atomic force microscope, spectroscopic ellipsometry and impedance spectroscopy. As-deposited amorphous films crystallized into tetragonal metastable phase of Mo5O14 on annealing at 500 °C in vacuum and air. This structure transformed to stable orthorhombic of MoO3 with annealing in oxygen environment. The optical parameters such as the refractive index, extinction coefficient, optical band gap energy and the Urbach energy were calculated from Cauchy formalism. Ellipsometric measurements reveal that the samples present optical gap located between 3.24 and 3.90 eV when the atmosphere becomes rich on oxygen. The variation of the conductivity in terms of the temperature shows an electrical behavior with oxygen environment. Finally, it has been found that MoO3 thin films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor.

  1. Oxygen Therapy

    MedlinePlus

    Oxygen therapy is a treatment that provides you with extra oxygen. Oxygen is a gas that your body needs to function. Normally, your lungs absorb oxygen from the air you breathe. But some conditions ...

  2. Influence of in-plane and bridging oxygen vacancies of SnO{sub 2} nanostructures on CH{sub 4} sensing at low operating temperatures

    SciTech Connect

    Bonu, Venkataramana Das, A. Prasad, Arun K.; Dhara, Sandip; Tyagi, A. K.; Krishna, Nanda Gopala

    2014-12-15

    Role of “O” defects in sensing pollutant with nanostructured SnO{sub 2} is not well understood, especially at low temperatures. SnO{sub 2} nanoparticles were grown by soft chemistry route followed by subsequent annealing treatment under specific conditions. Nanowires were grown by chemical vapor deposition technique. A systematic photoluminescence (PL) investigation of “O” defects in SnO{sub 2} nanostructures revealed a strong correlation between shallow donors created by the in-plane and the bridging “O” vacancies and gas sensing at low temperatures. These SnO{sub 2} nanostructures detected methane (CH{sub 4}), a reducing and green house gas at a low temperature of 50 °C. Response of CH{sub 4} was found to be strongly dependent on surface defect in comparison to surface to volume ratio. Control over “O” vacancies during the synthesis of SnO{sub 2} nanomaterials, as supported by X-ray photoelectron spectroscopy and subsequent elucidation for low temperature sensing are demonstrated.

  3. Morphology and gas sensing characteristics of density-controlled CuO nanostructures obtained by varying the oxygen partial pressure during growth

    NASA Astrophysics Data System (ADS)

    Lee, Dongjin; Jin, Changhyun; Noh, Youngwook; Park, Seokhyun; Choi, Sun-Woo

    2016-07-01

    By exerting different O2 partial pressures (0, 20, 40, and 60 sccm) onto copper substrates, we discovered that the growth parameter, namely, the O2 flow rate, affects the degree of nucleation, diameter, length, and crystalline quality of CuO nanowires (NWs). Scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to analyze the evolution of the morphological and the microstructural changes in the CuO nanostructures. The formation of a Cu2O interlayer between the Cu and the CuO layers could be adjusted by controlling more precisely the O2 flow rate. In addition, the reducing (H2S) and the oxidizing (O2, NO2, and SO2) gas sensing performances of these O2-assisted CuO NWs were compared with those of CuO NWs grown in static air. The response to the reducing H2S of the sensors based on CuO NWs grown using O2 at 40 sccm showed a higher electrical change and faster response and recovery times than the sensors based on CuO NWs grown using lower O2 flow rates, including the ones grown in static air and/or used for sensing oxidizing gases (O2, NO2, and SO2) did. On the basis of their growth and their gas-sensing applications, the possible mechanisms characteristic of the density-controlled CuO NWs grown using various O2 partial pressures are discussed.

  4. Relationships between high oxygen extraction fraction in the acute stage and final infarction in reversible middle cerebral artery occlusion: an investigation in anesthetized baboons with positron emission tomography.

    PubMed

    Young, A R; Sette, G; Touzani, O; Rioux, P; Derlon, J M; MacKenzie, E T; Baron, J C

    1996-11-01

    Studies in humans suggest that regions that show maximal increases in brain oxygen extraction fraction (OEF) in the hours following an ischemic episode are those most vulnerable for infarction and are often, although not always, associated with the final site of infarction. To clarify this issue, we followed the hemodynamic and metabolic characteristics of regions with an initially maximally increased OEF and compared them with the ultimately infarcted region in an experimental stroke model. Positron emission tomography (PET) was used to obtain functional images of the brain prior to and following reversible unilateral middle cerebral artery occlusion (MCAO) in 11 anesthetized baboons. To model early reperfusion, the clips were removed 6 h after occlusion. Successive measurements of regional CBF (rCBF), regional CMRO2 (rCMRO2), regional cerebral blood volume, and regional OEF (rOEF) were performed during the acute (up to 2 days) and chronic (> 15 days) stage. Late magnetic resonance imaging (MRI) scans (co-registered with PET) were obtained to identify infarction. Reversible MCAO produced an MRI-measurable infarction in 6 of 11 baboons; the others had no evidence of ischemic damage. Histological analysis confirmed the results of the MRI investigation but failed to show any evidence of cortical ischemic damage. The lesion was restricted to the head of the caudate nucleus, internal capsule, and putamen. The infarct volume obtained was 0.58 +/- 0.31 cm3. The infarcts were situated in the deep MCA territory, while the area of initially maximally increased OEF was within the cortical mantle. The mean absolute rCBF value in the infarct region of interest (ROI) was not significantly lower than in the highest-OEF ROI until 1-2 days post-MCAO. Cerebral metabolism in the deep MCA territory was always significantly lower than that of the cortical mantle; decreases in CMRO2 in the former region were evident as early as 1 h post-MCAO. In the cortical mantle, the rOEF was

  5. Wound Healing Essentials: Let There Be Oxygen

    PubMed Central

    Sen, Chandan K.

    2009-01-01

    The state of wound oxygenation is a key determinant of healing outcomes. From a diagnostic standpoint, measurements of wound oxygenation are commonly used to guide treatment planning such as amputation decision. In preventive applications, optimizing wound perfusion and providing supplemental O2 in the peri-operative period reduces the incidence of post-operative infections. Correction of wound pO2 may, by itself, trigger some healing responses. Importantly, approaches to correct wound pO2 favorably influence outcomes of other therapies such as responsiveness to growth factors and acceptance of grafts. Chronic ischemic wounds are essentially hypoxic. Primarily based on the tumor literature, hypoxia is generally viewed as being angiogenic. This is true with the condition that hypoxia be acute and mild to modest in magnitude. Extreme near-anoxic hypoxia, as commonly noted in problem wounds, is not compatible with tissue repair. Adequate wound tissue oxygenation is required but may not be sufficient to favorably influence healing outcomes. Success in wound care may be improved by a personalized health care approach. The key lies in our ability to specifically identify the key limitations of a given wound and in developing a multifaceted strategy to specifically address those limitations. In considering approaches to oxygenate the wound tissue it is important to recognize that both too little as well as too much may impede the healing process. Oxygen dosing based on the specific need of a wound therefore seems prudent. Therapeutic approaches targeting the oxygen sensing and redox signaling pathways are promising. PMID:19152646

  6. Composite nanofibers doped with a phosphorescent Re(I) complex having restricted conjugation plane in its diamine ligand: preparation, characterization, photophysical property and oxygen-sensing performance.

    PubMed

    Lin, Chen; Shaoyan, Wang; Qi, Wang; Jing, Li

    2013-10-01

    In this paper, we report a Re(I) complex of Re(CO)3(Cl-PYO)Br, where Cl-PYO stands for 2-(4-chlorophenyl)-5-(pyridin-2-yl)-1,3,4-oxadiazole, including its synthesis, identification, molecular structure, theoretical calculation and photophysical character. Re(CO)3(Cl-PYO)Br is found to be a yellow emitter with long excited state lifetime in pure N2 atmosphere. Theoretical calculation result suggests that this emission comes from a triplet metal-to-ligand-charge-transfer excited state. By doping Re(CO)3(Cl-PYO)Br into a polymer supporting matrix of poly(vinylpyrrolidone), the emission of the resulted composite materials is found to be sensitive towards various oxygen concentrations. The maximum sensitivity is obtained to be 7.88. Owing to the porous structure of fibrous poly(vinylpyrrolidone) matrix, a short response time of 11s towards molecular oxygen is also realized with high photostability.

  7. FlpS, the FNR-Like Protein of Streptococcus suis Is an Essential, Oxygen-Sensing Activator of the Arginine Deiminase System

    PubMed Central

    Willenborg, Jörg; Koczula, Anna; Fulde, Marcus; de Greeff, Astrid; Beineke, Andreas; Eisenreich, Wolfgang; Huber, Claudia; Seitz, Maren; Valentin-Weigand, Peter; Goethe, Ralph

    2016-01-01

    Streptococcus (S.) suis is a zoonotic pathogen causing septicemia and meningitis in pigs and humans. During infection S. suis must metabolically adapt to extremely diverse environments of the host. CcpA and the FNR family of bacterial transcriptional regulators are important for metabolic gene regulation in various bacteria. The role of CcpA in S. suis is well defined, but the function of the FNR-like protein of S. suis, FlpS, is yet unknown. Transcriptome analyses of wild-type S. suis and a flpS mutant strain suggested that FlpS is involved in the regulation of the central carbon, arginine degradation and nucleotide metabolism. However, isotopologue profiling revealed no substantial changes in the core carbon and amino acid de novo biosynthesis. FlpS was essential for the induction of the arcABC operon of the arginine degrading pathway under aerobic and anaerobic conditions. The arcABC-inducing activity of FlpS could be associated with the level of free oxygen in the culture medium. FlpS was necessary for arcABC-dependent intracellular bacterial survival but redundant in a mice infection model. Based on these results, we propose that the core function of S. suis FlpS is the oxygen-dependent activation of the arginine deiminase system. PMID:27455333

  8. Composite nanofibers doped with a phosphorescent Re(I) complex having restricted conjugation plane in its diamine ligand: Preparation, characterization, photophysical property and oxygen-sensing performance

    NASA Astrophysics Data System (ADS)

    Lin, Chen; Shaoyan, Wang; Qi, Wang; Jing, Li

    2013-10-01

    In this paper, we report a Re(I) complex of Re(CO)3(Cl-PYO)Br, where Cl-PYO stands for 2-(4-chlorophenyl)-5-(pyridin-2-yl)-1,3,4-oxadiazole, including its synthesis, identification, molecular structure, theoretical calculation and photophysical character. Re(CO)3(Cl-PYO)Br is found to be a yellow emitter with long excited state lifetime in pure N2 atmosphere. Theoretical calculation result suggests that this emission comes from a triplet metal-to-ligand-charge-transfer excited state. By doping Re(CO)3(Cl-PYO)Br into a polymer supporting matrix of poly(vinylpyrrolidone), the emission of the resulted composite materials is found to be sensitive towards various oxygen concentrations. The maximum sensitivity is obtained to be 7.88. Owing to the porous structure of fibrous poly(vinylpyrrolidone) matrix, a short response time of 11 s towards molecular oxygen is also realized with high photostability.

  9. FlpS, the FNR-Like Protein of Streptococcus suis Is an Essential, Oxygen-Sensing Activator of the Arginine Deiminase System.

    PubMed

    Willenborg, Jörg; Koczula, Anna; Fulde, Marcus; de Greeff, Astrid; Beineke, Andreas; Eisenreich, Wolfgang; Huber, Claudia; Seitz, Maren; Valentin-Weigand, Peter; Goethe, Ralph

    2016-07-21

    Streptococcus (S.) suis is a zoonotic pathogen causing septicemia and meningitis in pigs and humans. During infection S. suis must metabolically adapt to extremely diverse environments of the host. CcpA and the FNR family of bacterial transcriptional regulators are important for metabolic gene regulation in various bacteria. The role of CcpA in S. suis is well defined, but the function of the FNR-like protein of S. suis, FlpS, is yet unknown. Transcriptome analyses of wild-type S. suis and a flpS mutant strain suggested that FlpS is involved in the regulation of the central carbon, arginine degradation and nucleotide metabolism. However, isotopologue profiling revealed no substantial changes in the core carbon and amino acid de novo biosynthesis. FlpS was essential for the induction of the arcABC operon of the arginine degrading pathway under aerobic and anaerobic conditions. The arcABC-inducing activity of FlpS could be associated with the level of free oxygen in the culture medium. FlpS was necessary for arcABC-dependent intracellular bacterial survival but redundant in a mice infection model. Based on these results, we propose that the core function of S. suis FlpS is the oxygen-dependent activation of the arginine deiminase system.

  10. The acute effects of low flow oxygen and isosorbide dinitrate on left and right ventricular ejection fractions in chronic obstructive pulmonary disease

    SciTech Connect

    Morrison, D.; Caldwell, J.; Lakshminaryan, S.; Ritchie, J.L.; Kennedy, J.W.

    1983-10-01

    The objectives of this study were to determine the effects of low flow oxygen and isosorbide dinitrate on rest and exercise biventricular ejection fractions in patients with chronic obstructive pulmonary disease and to relate these ejection fraction responses to changes in pressure and flow. Nine patients with stable, moderate to severe chronic obstructive pulmonary disease who had no prior history of heart failure performed supine exercise with simultaneous hemodynamic and radionuclide ventriculographic monitoring. Eight patients performed a second exercise during low flow oxygen breathing and five performed a third exercise after ingesting 10 mg oral isosorbide. Oxygen led to a decrease in exercise pulmonary artery pressure in all subjects and a decline in total pulmonary resistance in five of the seven in whom it was measured. Right ventricular ejection fraction increased 0.05 or more only in subjects who had a decrease in total pulmonary resistance. Isosorbide led to an increase in rest and exercise right and left ventricular ejection fractions with simultaneous decreases in pulmonary artery pressure, total pulmonary resistance, blood pressure and arterial oxygen tension. These results suggest that in patients with chronic obstructive pulmonary disease but without a history of right heart failure, the right ventricular systolic functional response to low flow oxygen and isosorbide at rest and exercise is, in part, determined by changes in total pulmonary resistance. The chronic relation between right ventricular ejection fraction and pulmonary hemodynamics in patients with chronic obstructive pulmonary disease remains to be evaluated.

  11. Effects of Acute Bleeding Followed by Hydroxyethyl Starch 130/0.4 or a Crystalloid on Propofol Concentrations, Cerebral Oxygenation, and Electroencephalographic and Haemodynamic Variables in Pigs

    PubMed Central

    Venâncio, Carlos; Souza, Almir P.; Ferreira, Luísa Maria; Branco, Paula Sério; de Pinho, Paula Guedes; Amorim, Pedro; Ferreira, David A.

    2014-01-01

    Bleeding changes the haemodynamics, compromising organ perfusion. In this study, the effects of bleeding followed by replacement with hydroxyethyl starch 130/0.4 (HES) or lactated Ringer's (LR) on cerebral oxygenation and electroencephalogram-derived parameters were investigated. Twelve young pigs under propofol-remifentanil anaesthesia were bled 30 mL/kg and, after a 20-minute waiting period, volume replacement was performed with HES (GHES; N = 6) or LR (GRL; N = 6). Bleeding caused a decrease of more than 50% in mean arterial pressure (P < 0.01) and a decrease in cerebral oximetry (P = 0.039), bispectral index, and electroencephalogram total power (P = 0.04 and P < 0.01, resp.), while propofol plasma concentrations increased (P < 0.01). Both solutions restored the haemodynamics and cerebral oxygenation similarly and were accompanied by an increase in electroencephalogram total power. No differences between groups were found. However, one hour after the end of the volume replacement, the cardiac output (P = 0.03) and the cerebral oxygenation (P = 0.008) decreased in the GLR and were significantly lower than in GHES (P = 0.02). Volume replacement with HES 130/0.4 was capable of maintaining the cardiac output and cerebral oxygenation during a longer period than LR and caused a decrease in the propofol plasma concentrations. PMID:24971192

  12. Surface acoustic wave oxygen sensor

    NASA Technical Reports Server (NTRS)

    Collman, James P.; Oglesby, Donald M.; Upchurch, Billy T.; Leighty, Bradley D.; Zhang, Xumu; Herrmann, Paul C.

    1994-01-01

    A surface acoustic wave (SAW) device that responds to oxygen pressure was developed by coating a 158 MHz quartz surface acoustic wave (SAW) device with an oxygen binding agent. Two types of coatings were used. One type was prepared by dissolving an oxygen binding agent in a toluene solution of a copolymer containing the axial ligand. A second type was prepared with an oxygen binding porphyrin solution containing excess axial ligand without a polymer matrix. In the polymer based coatings, the copolymer served to provide the axial ligand to the oxygen binding agent and as a coating matrix on the surface of the SAW device. The oxygen sensing SAW device has been shown to bind oxygen following a Langmuir isotherm and may be used to measure the equilibrium constant of the oxygen binding compound in the coating matrix.

  13. Reactive oxygen species levels and DNA fragmentation on astrocytes in primary culture after acute exposure to low intensity microwave electromagnetic field.

    PubMed

    Campisi, Agata; Gulino, Marisa; Acquaviva, Rosaria; Bellia, Paolo; Raciti, Giuseppina; Grasso, Rosaria; Musumeci, Francesco; Vanella, Angelo; Triglia, Antonio

    2010-03-31

    The exposure of primary rat neocortical astroglial cell cultures to acute electromagnetic fields (EMF) in the microwave range was studied. Differentiated astroglial cell cultures at 14 days in vitro were exposed for 5, 10, or 20min to either 900MHz continuous waves or 900MHz waves modulated in amplitude at 50Hz using a sinusoidal waveform and 100% modulation index. The strength of the electric field (rms value) at the sample position was 10V/m. No change in cellular viability evaluated by MTT test and lactate dehydrogenase release was observed. A significant increase in ROS levels and DNA fragmentation was found only after exposure of the astrocytes to modulated EMF for 20min. No evident effects were detected when shorter time intervals or continuous waves were used. The irradiation conditions allowed the exclusion of any possible thermal effect. Our data demonstrate, for the first time, that even acute exposure to low intensity EMF induces ROS production and DNA fragmentation in astrocytes in primary cultures, which also represent the principal target of modulated EMF. Our findings also suggest the hypothesis that the effects could be due to hyperstimulation of the glutamate receptors, which play a crucial role in acute and chronic brain damage. Furthermore, the results show the importance of the amplitude modulation in the interaction between EMF and neocortical astrocytes.

  14. Pressure Physiology: Studies of Acute and Chronic Exposures to Increased Pressures of Oxygen and Inert Gases in Diving, Decompression and Therapy of Decompression and Isobaric Gas Lesion Diseases

    DTIC Science & Technology

    1985-12-31

    Jr. and E.D. Thalmann. CNS oxygen toxicity in closed - circuit scuba divers. In: Underwater Physiology VIII, ed. by Bachrach, A.J. and Matzen, M.M...residual capacity, total lung capacity), closing volumes, carbon monoxide diffusing capacity, alveolar-arterial P02 and PCO2 values, static and dynamic...inspiratory and expiratory reserve volume, residual volume, functional residual capacity, total lung capacity), closing volumes, carbon monoxide

  15. Neurohistological Investiations on General Oxygen Deficiency of the Brain - The Morphological Behavior of the Ganglion Cells After Generalized Acute and Subacute Hypoxia

    DTIC Science & Technology

    1951-02-01

    factitious- ness, it appears reasonable to apply the term mofpbotropic mortal necrobiosis also to ganglion cell changes after acute death« Consequently... necrobiosis can.b^ applied PROJEGT’ÜÜMBER 21-23-W4* REPORTNÜMjBER 1 in the present connection as well» Whenever a new term is introduced, one has to make...Occasionally, one can observe a mörphötropic necrobiosis of intravital origin within a morpbo- trppic mortal necrobiosis . We examined one case, for

  16. Using oxygen at home

    MedlinePlus

    Oxygen - home use; COPD - home oxygen; Chronic obstructive airways disease - home oxygen; Chronic obstructive lung disease - home oxygen; Chronic bronchitis - home oxygen; Emphysema - home oxygen; Chronic respiratory ...

  17. HISTONE DEACETYLASE ACTIVITY AND REACTIVE OXYGEN SPECIES CONTENT IN THE TISSUE CULTURE OF Arabidopsis thaliana UNDER NORMAL CONDITIONS AND DEVELOPMENT OF ACUTE OSMOTIC STRESS.

    PubMed

    Jadko, S I

    2015-01-01

    The possible involvement of histone deacetylase (HDAC) in regulation of ROS content in the tissue culture of Arabidopsis thaliana under normal conditions and under development of acute osmotic stress was studied by using inhibition assay with application of trichostatin A (TSA). It was found that in the tissue culture grown under normal conditions a decrease in HDAC activity by means of TSA led to increase of the ROS content. Similar but more pronounced alterations occurred under stress. At the same time an increase in histone acetyltransferase (HAT) activity was also observed. The possible mechanisms of HDAC and HAT participation in regulation of ROS content by changes in expression of genes that are responsible for ROS production and antioxidant activity are discussed.

  18. Selective TNF-α targeting with infliximab attenuates impaired oxygen metabolism and contractile function induced by an acute exposure to air particulate matter.

    PubMed

    Marchini, Timoteo; D'Annunzio, Verónica; Paz, Mariela L; Cáceres, Lourdes; Garcés, Mariana; Perez, Virginia; Tasat, Deborah; Vanasco, Virginia; Magnani, Natalia; Gonzalez Maglio, Daniel; Gelpi, Ricardo J; Alvarez, Silvia; Evelson, Pablo

    2015-11-15

    Inflammation plays a central role in the onset and progression of cardiovascular diseases associated with the exposure to air pollution particulate matter (PM). The aim of this work was to analyze the cardioprotective effect of selective TNF-α targeting with a blocking anti-TNF-α antibody (infliximab) in an in vivo mice model of acute exposure to residual oil fly ash (ROFA). Female Swiss mice received an intraperitoneal injection of infliximab (10 mg/kg body wt) or saline solution, and were intranasally instilled with a ROFA suspension (1 mg/kg body wt). Control animals were instilled with saline solution and handled in parallel. After 3 h, heart O2 consumption was assessed by high-resolution respirometry in left ventricle tissue cubes and isolated mitochondria, and ventricular contractile reserve and lusitropic reserve were evaluated according to the Langendorff technique. ROFA instillation induced a significant decrease in tissue O2 consumption and active mitochondrial respiration by 32 and 31%, respectively, compared with the control group. While ventricular contractile state and isovolumic relaxation were not altered in ROFA-exposed mice, impaired contractile reserve and lusitropic reserve were observed in this group. Infliximab pretreatment significantly attenuated the decrease in heart O2 consumption and prevented the decrease in ventricular contractile and lusitropic reserve in ROFA-exposed mice. Moreover, infliximab-pretreated ROFA-exposed mice showed conserved left ventricular developed pressure and cardiac O2 consumption in response to a β-adrenergic stimulus with isoproterenol. These results provides direct evidence linking systemic inflammation and altered cardiac function following an acute exposure to PM and contribute to the understanding of PM-associated cardiovascular morbidity and mortality.

  19. Oxygen analyzer

    DOEpatents

    Benner, William H.

    1986-01-01

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N.sub.2), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable oxygen obtained by decomposing the sample at 1135.degree. C., or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135.degree. C. as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N.sub.2, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  20. Oxygen Therapy

    MedlinePlus

    ... stored as a gas or liquid in special tanks. These tanks can be delivered to your home and contain ... they won’t run out of oxygen. Portable tanks and oxygen concentrators may make it easier for ...

  1. Reactive oxygen species produced by NADPH oxidase and mitochondrial dysfunction in lung after an acute exposure to Residual Oil Fly Ashes

    SciTech Connect

    Magnani, Natalia D.; Marchini, Timoteo; Vanasco, Virginia; Tasat, Deborah R.; Alvarez, Silvia; Evelson, Pablo

    2013-07-01

    Reactive O{sub 2} species production triggered by particulate matter (PM) exposure is able to initiate oxidative damage mechanisms, which are postulated as responsible for increased morbidity along with the aggravation of respiratory diseases. The aim of this work was to quantitatively analyse the major sources of reactive O{sub 2} species involved in lung O{sub 2} metabolism after an acute exposure to Residual Oil Fly Ashes (ROFAs). Mice were intranasally instilled with a ROFA suspension (1.0 mg/kg body weight), and lung samples were analysed 1 h after instillation. Tissue O{sub 2} consumption and NADPH oxidase (Nox) activity were evaluated in tissue homogenates. Mitochondrial respiration, respiratory chain complexes activity, H{sub 2}O{sub 2} and ATP production rates, mitochondrial membrane potential and oxidative damage markers were assessed in isolated mitochondria. ROFA exposure was found to be associated with 61% increased tissue O{sub 2} consumption, a 30% increase in Nox activity, a 33% increased state 3 mitochondrial O{sub 2} consumption and a mitochondrial complex II activity increased by 25%. During mitochondrial active respiration, mitochondrial depolarization and a 53% decreased ATP production rate were observed. Neither changes in H{sub 2}O{sub 2} production rate, nor oxidative damage in isolated mitochondria were observed after the instillation. After an acute ROFA exposure, increased tissue O{sub 2} consumption may account for an augmented Nox activity, causing an increased O{sub 2}{sup ·−} production. The mitochondrial function modifications found may prevent oxidative damage within the organelle. These findings provide new insights to the understanding of the mechanisms involving reactive O{sub 2} species production in the lung triggered by ROFA exposure. - Highlights: • Exposure to ROFA alters the oxidative metabolism in mice lung. • The augmented Nox activity contributes to the high tissue O{sub 2} consumption. • Exposure to ROFA

  2. [Apneic oxygenation].

    PubMed

    Alekseev, A V; Vyzhigina, M A; Parshin, V D; Fedorov, D S

    2013-01-01

    Recent technological advances in thoracic and tracheal surgery make the anaesthesiologist use different respiratory techniques during the operation. Apneic oxygenation is a one of alternative techniques. This method is relatively easy in use, does not require special expensive equipment and is the only possible technique in several clinical situations when other respiratory methods are undesirable or cannot be used. However there is no enough information about apneic oxygenation in Russian. This article reviews publications about apneic oxygenation. The review deals with experiments on diffusion respiration in animals, physiological changes during apneic oxygenation in man and defines clinical cases when apneic oxygenation can be used.

  3. Acute oxygenation changes on ischemic foot of a novel intermittent pneumatic compression device and of an existing sequential device in severe peripheral arterial disease

    PubMed Central

    2014-01-01

    Background Intermittent pneumatic compression (IPC) improves haemodynamics in peripheral arterial disease (PAD), but its effects on foot perfusion were scarcely studied. In severe PAD patients we measured the foot oxygenation changes evoked by a novel intermittent IPC device (GP), haemodynamics and compliance to the treatment. Reference values were obtained by a sequential foot-calf device (SFC). Methods Twenty ischemic limbs (Ankle-Brachial Index = 0.5 ± 0.2) of 12 PAD patients (7 male, age: 74.5 ± 10.8 y) with an interval of 48 ± 2 hours received a 35 minute treatment in supine position with two IPC devices: i) a Gradient Pump (GP), which slowly inflates a single thigh special sleeve and ii) an SFC (ArtAssist®, ACI Medical, San Marcos, CA, USA), which rapidly inflates two foot-calf sleeves. Main outcome measure: changes of oxygenated haemoglobin at foot (HbO2foot) by continuous near-infrared spectroscopy recording and quantified as area-under-curve (AUC) for periods of 5 minutes. Other measures: haemodynamics by echo-colour Doppler (time average velocity (TAV) and blood flow (BF) in the popliteal artery and in the femoral vein), patient compliance by a properly developed form. Results All patients completed the treatment with GP, 9 with SFC. HbO2foot during the working phase, considered as average value of the 5 minutes periods, increased with GP (AUC 458 ± 600 to 1216 ± 280) and decreased with SFC (AUC 231 ± 946 to −1088 ± 346), significantly for most periods (P < 0.05). The GP treatment was associated to significant haemodynamic changes from baseline to end of the treatment (TAV = 10.2 ± 3.3 to 13.5 ± 5.5 cm/sec, P = 0.004; BF = 452.0 ± 187.2 to 607.9 ± 237.8 ml/sec, P = 0.0001), not observed with SFC (TAV = 11.2 ± 3.4 to 11.8 ± 4.3 cm/sec; BF = 513.8 ± 203.7 to 505.9 ± 166.5 ml/min, P = n.s.). GP obtained a higher score of patient

  4. Novel nanostructured oxygen sensor

    NASA Astrophysics Data System (ADS)

    Boardman, Alan James

    New government regulations and industry requirements for medical oxygen sensors require the development of alternate materials and process optimization of primary sensor components. Current oxygen sensors are not compliant with the Restriction of Hazardous Substances (RoHS) Directive. This work focused on two areas. First, was finding suitable readily available materials for the sensor anodes. Second was optimizing the processing of the sensor cathode membrane for reduced delamination. Oxygen sensors were made using tin (Sn) and bismuth (Bi) electrodes, potassium hydroxide (KOH) and acetic acid (CH3COOH) electrolytes with platinum (Pt) and gold (Au) reference electrodes. Bi electrodes were fabricated by casting and pressing processes. Electrochemical characterization of the Sn and Bi electrodes was performed by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and sensing characterization per BSEN ISO 21647:2009 at various oxygen percentages, 0%, 20.9% and 100% oxygen levels with an automated test apparatus. The Sn anode with both electrolyte solutions showed good oxygen sensing properties and performance in a sensor. This system shows promise for replacement of Pb electrodes as required by the RoHS Directive. The Bi anode with Au cathode in both KOH and CH3COOH electrolytes showed acceptable performance and oxygen sensing properties. The Bi anodes fabricated by separate manufacturing methods demonstrated effectiveness for use in medical oxygen sensors. Gold thin films were prepared by magnetron sputtering on Flouroethylene Polymer (FEP) films. The FEP substrate temperature ranged from -77°C to 50°C. X-Ray Diffraction (XRD) and 4-point resistivity characterized the effects of substrate temperature to Au thin film particle size. XRD peak broadening and resistivity measurements showed a strong correlation of particle size to FEP substrate temperature. Particle size at 50°C was 594A and the -77°C particle size was 2.4 x 103A. Substrate

  5. Improved arterial oxygenation with biologically variable or fractal ventilation using low tidal volumes in a porcine model of acute respiratory distress syndrome.

    PubMed

    Boker, Abdulaziz; Graham, M Ruth; Walley, Keith R; McManus, Bruce M; Girling, Linda G; Walker, Elizabeth; Lefevre, Gerald R; Mutch, W Alan C

    2002-02-15

    We compared biologically variable ventilation (V (bv); n = 9) with control mode ventilation (V (c); n = 8) at low tidal volume (VT)--initial 6 ml/kg--in a porcine model of acute respiratory distress syndrome (ARDS). Hemodynamics, respiratory gases, airway pressures, and VT data were measured. Static P-V curves were generated at 5 h. Interleukin (IL)-8 and IL-10 were measured in serum and tracheal aspirate. By 5 h, higher Pa(O(2)) (173 +/- 30 mm Hg versus 119 +/- 23 mm Hg; mean +/- SD; p < 0.0001 group x time interaction [G x T]), lower shunt fraction (6 +/- 1% versus 9 +/- 3%; p = 0.0026, G x T) at lower peak airway pressure (21 +/- 2 versus 24 +/- 1 cm H(2)O; p = 0.0342; G x T) occurred with V (bv). IL-8 concentrations in tracheal aspirate and wet:dry weight ratios were inversely related; p = 0.011. With V (c), IL-8 concentrations were 3.75-fold greater at wet:dry weight ratio of 10. IL-10 concentrations did not differ between groups. In both groups, ventilation was on the linear portion of the P-V curve. With V (bv), VT variability demonstrated an inverse power law indicating fractal behavior. In this model of ARDS, V (bv) improved Pa(O(2)) at lower peak airway pressure and IL-8 levels compared with V (c).

  6. Oxygen analyzer

    DOEpatents

    Benner, W.H.

    1984-05-08

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N/sub 2/), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable obtained by decomposing the sample at 1135/sup 0/C, or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135/sup 0/C as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N/sub 2/, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  7. Cerebral blood flow, frontal lobe oxygenation and intra-arterial blood pressure during sprint exercise in normoxia and severe acute hypoxia in humans.

    PubMed

    Curtelin, David; Morales-Alamo, David; Torres-Peralta, Rafael; Rasmussen, Peter; Martin-Rincon, Marcos; Perez-Valera, Mario; Siebenmann, Christoph; Pérez-Suárez, Ismael; Cherouveim, Evgenia; Sheel, A William; Lundby, Carsten; Calbet, José Al

    2017-01-01

    Cerebral blood flow (CBF) is regulated to secure brain O2 delivery while simultaneously avoiding hyperperfusion; however, both requisites may conflict during sprint exercise. To determine whether brain O2 delivery or CBF is prioritized, young men performed sprint exercise in normoxia and hypoxia (PIO2 = 73 mmHg). During the sprints, cardiac output increased to ∼22 L min(-1), mean arterial pressure to ∼131 mmHg and peak systolic blood pressure ranged between 200 and 304 mmHg. Middle-cerebral artery velocity (MCAv) increased to peak values (∼16%) after 7.5 s and decreased to pre-exercise values towards the end of the sprint. When the sprints in normoxia were preceded by a reduced PETCO2, CBF and frontal lobe oxygenation decreased in parallel ( r = 0.93, P < 0.01). In hypoxia, MCAv was increased by 25%, due to a 26% greater vascular conductance, despite 4-6 mmHg lower PaCO2 in hypoxia than normoxia. This vasodilation fully accounted for the 22 % lower CaO2 in hypoxia, leading to a similar brain O2 delivery during the sprints regardless of PIO2. In conclusion, when a conflict exists between preserving brain O2 delivery or restraining CBF to avoid potential damage by an elevated perfusion pressure, the priority is given to brain O2 delivery.

  8. The Acute Effects of a Single Session of Expiratory Muscle Strength Training on Blood Pressure, Heart Rate, and Oxygen Saturation in Healthy Adults

    PubMed Central

    Laciuga, Helena; Davenport, Paul; Sapienza, Christine

    2012-01-01

    Expiratory muscle strength training (EMST) is a rehabilitative program that has been tested for outcomes related to respiratory muscle strength, cough, swallow, and voice function in healthy young adult, elderly individuals, and in patients with progressive neurodegenerative disease. Because EMST has been used in patient care, the associated cardiovascular responses during EMST are of importance. This study investigated the changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and oxygen saturation (SpO2) during one session of EMST in healthy, young adults as a preliminary study of device safety. Thirty-one participants completed a single session of 25 trials with the EMST device. Valsalva maneuvers were performed at the beginning and at the end of the EMST trials for task comparison. The SBP, DBP, HR, and SpO2 were recorded at the baseline and after completing the following tasks: a Valsalva maneuver, 12 trials using the EMST device, 13 trials using the EMST device, and 5 min of rest following the EMST session. A mixed linear model tested for changes across the six time points. The results indicated no significant change of SBP, DBP, HR, or SpO2 during or following the EMST trials or after performing the Valsalva maneuver. The results suggest that EMST does not elicit significant fluctuations of blood pressure, HR, and SpO2 in healthy young adults even when considering the effects of covariates on the outcomes measures. PMID:22419910

  9. DEVICE FOR CONTROL OF OXYGEN PARTIAL PRESSURE

    DOEpatents

    Bradner, H.; Gordon, H.S.

    1957-12-24

    A device is described that can sense changes in oxygen partial pressure and cause a corresponding mechanical displacement sufficient to actuate meters, valves and similar devices. A piston and cylinder arrangement contains a charge of crystalline metal chelate pellets which have the peculiar property of responding to variations in the oxygen content of the ambient atmosphere by undergoing a change in dimension. A lever system amplifies the relative displacement of the piston in the cylinder, and actuates the controlled valving device. This partial pressure oxygen sensing device is useful in controlled chemical reactions or in respiratory devices such as the oxygen demand meters for high altitude aircraft.

  10. The Effects of Acutely Administered 3,4-Methylenedioxymethamphetamine on Spontaneous Brain Function in Healthy Volunteers Measured with Arterial Spin Labeling and Blood Oxygen Level–Dependent Resting State Functional Connectivity

    PubMed Central

    Carhart-Harris, Robin L.; Murphy, Kevin; Leech, Robert; Erritzoe, David; Wall, Matthew B.; Ferguson, Bart; Williams, Luke T.J.; Roseman, Leor; Brugger, Stefan; De Meer, Ineke; Tanner, Mark; Tyacke, Robin; Wolff, Kim; Sethi, Ajun; Bloomfield, Michael A.P.; Williams, Tim M.; Bolstridge, Mark; Stewart, Lorna; Morgan, Celia; Newbould, Rexford D.; Feilding, Amanda; Curran, H. Val; Nutt, David J.

    2015-01-01

    Background The compound 3,4-methylenedioxymethamphetamine (MDMA) is a potent monoamine releaser that produces an acute euphoria in most individuals. Methods In a double-blind, placebo-controlled, balanced-order study, MDMA was orally administered to 25 physically and mentally healthy individuals. Arterial spin labeling and seed-based resting state functional connectivity (RSFC) were used to produce spatial maps displaying changes in cerebral blood flow (CBF) and RSFC after MDMA administration. Participants underwent two arterial spin labeling and two blood oxygen level–dependent scans in a 90-minute scan session; MDMA and placebo study days were separated by 1 week. Results Marked increases in positive mood were produced by MDMA. Decreased CBF only was observed after MDMA, and this was localized to the right medial temporal lobe (MTL), thalamus, inferior visual cortex, and the somatosensory cortex. Decreased CBF in the right amygdala and hippocampus correlated with ratings of the intensity of global subjective effects of MDMA. The RSFC results complemented the CBF results, with decreases in RSFC between midline cortical regions, the medial prefrontal cortex, and MTL regions, and increases between the amygdala and hippocampus. There were trend-level correlations between these effects and ratings of intense and positive subjective effects. Conclusions The MTLs appear to be specifically implicated in the mechanism of action of MDMA, but further work is required to elucidate how the drug’s characteristic subjective effects arise from its modulation of spontaneous brain activity. PMID:24495461

  11. Preventing LVAD implantation by early short-term mechanical support and prolonged inodilator therapy : A case series with acute refractory cardiogenic shock treated with veno-arterial extracorporeal membrane oxygenation and optimised medical strategy.

    PubMed

    Brugts, J J; Manintveld, O; Constantinescu, A; Donker, D W; van Thiel, R J; Nieman, K; Jewbali, L S D; Zijlstra, F; Caliskan, K

    2014-04-01

    Cardiogenic shock continues to be a life-threatening condition carrying a high mortality and morbidity, where the prognosis remains poor despite intensive modern treatment modalities. In recent years, mainly technical improvements have led to a more widespread use of short- and long-term mechanical circulatory support, such as veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and left ventricular assist devices (LVADs). Currently, LVADs are indispensable as 'bridge' to cardiac recovery, heart transplantation (HTX), and/or as destination therapy Importantly, both LVADs and HTX put a vast burden on financial resources, besides significant short- and long-term risks of morbidity and mortality. These considerations underscore the importance of optimal timing and appropriate patient selection for LVAD therapy, avoiding as much as possible an unfortunate and costly clinical path. In this report, we present a series of three cases with acute refractory cardiogenic shock ('crash and burn', INTERMACS profile 1) successfully treated by ECMO and early optimal medical therapy preventing a certain path towards LVAD and/or HTX, for which they were initially referred. This conservative approach in INTERMACS profile one patients warrants very early introduction of adequate medical heart failure therapy under the umbrella of a combination of short-term mechanical circulatory and inotropic support by phosphodiesterase inhibitors. Therefore, this novel combined medical-mechanical approach could have important clinical implications for this extremely challenging patient category, as it may avoid an unnecessary and costly clinical path towards LVAD and/or heart transplantation.

  12. Appreciating Oxygen

    ERIC Educational Resources Information Center

    Weiss, Hilton M.

    2008-01-01

    Photosynthetic flora and microfauna utilize light from the sun to convert carbon dioxide and water into carbohydrates and oxygen. While these carbohydrates and their derivative hydrocarbons are generally considered to be fuels, it is the thermodynamically energetic oxygen molecule that traps, stores, and provides almost all of the energy that…

  13. Oxygen control of breathing by an olfactory receptor activated by lactate

    PubMed Central

    Chang, Andy J.; Ortega, Fabian E.; Riegler, Johannes; Madison, Daniel V.; Krasnow, Mark A.

    2015-01-01

    Summary Animals have evolved homeostatic responses to changes in oxygen availability that act on different time scales. Although the hypoxia-inducible factor (HIF) transcriptional pathway that controls long term responses to low oxygen (hypoxia) has been established1, the pathway that mediates acute responses to hypoxia in mammals is not well understood. Here we show that the olfactory receptor Olfr78 is highly and selectively expressed in oxygen-sensitive glomus cells of the carotid body, a chemosensory organ at the carotid artery bifurcation that monitors blood oxygen and stimulates breathing within seconds when oxygen declines2. Olfr78 mutants fail to increase ventilation in hypoxia but respond normally to hypercapnia. Glomus cells are present in normal numbers and appear structurally intact, but hypoxia-induced carotid body activity is diminished. Lactate, a metabolite that rapidly accumulates in hypoxia and induces hyperventilation3–6, activates Olfr78 in heterologous expression experiments, induces calcium transients in glomus cells, and stimulates carotid sinus nerve activity through Olfr78. We propose that in addition to its role in olfaction, Olfr78 acts as a hypoxia sensor in the breathing circuit by sensing lactate produced when oxygen levels decline. PMID:26560302

  14. The extracellular calcium-sensing receptor is required for cholecystokinin secretion in response to L-phenylalanine in acutely isolated intestinal I cells.

    PubMed

    Liou, Alice P; Sei, Yoshitatsu; Zhao, Xilin; Feng, Jianying; Lu, Xinping; Thomas, Craig; Pechhold, Susanne; Raybould, Helen E; Wank, Stephen A

    2011-04-01

    The extracellular calcium-sensing receptor (CaSR) has recently been recognized as an L-amino acid sensor and has been implicated in mediating cholecystokinin (CCK) secretion in response to aromatic amino acids. We investigated whether direct detection of L-phenylalanine (L-Phe) by CaSR results in CCK secretion in the native I cell. Fluorescence-activated cell sorting of duodenal I cells from CCK-enhanced green fluorescent protein (eGFP) transgenic mice demonstrated CaSR gene expression. Immunostaining of fixed and fresh duodenal tissue sections confirmed CaSR protein expression. Intracellular calcium fluxes were CaSR dependent, stereoselective for L-Phe over D-Phe, and responsive to type II calcimimetic cinacalcet in CCK-eGFP cells. Additionally, CCK secretion by an isolated I cell population was increased by 30 and 62% in response to L-Phe in the presence of physiological (1.26 mM) and superphysiological (2.5 mM) extracellular calcium concentrations, respectively. While the deletion of CaSR from CCK-eGFP cells did not affect basal CCK secretion, the effect of L-Phe or cinacalcet on intracellular calcium flux was lost. In fact, both secretagogues, as well as superphysiological Ca(2+), evoked an unexpected 20-30% decrease in CCK secretion compared with basal secretion in CaSR(-/-) CCK-eGFP cells. CCK secretion in response to KCl or tryptone was unaffected by the absence of CaSR. The present data suggest that CaSR is required for hormone secretion in the specific response to L-Phe by the native I cell, and that a receptor-mediated mechanism may inhibit hormone secretion in the absence of a fully functional CaSR.

  15. High Temperature Langasite SAW Oxygen Sensor

    SciTech Connect

    Zheng, Peng; Chin, Tao-Lun; Greve, David; Oppenheim, Irving; Malone, Vanessa; Cao, Limin

    2011-08-01

    High-temperature langasite SAW oxygen sensors using sputtered ZnO as a resistive gas-sensing layer were fabricated and tested. Sensitivity to oxygen gas was observed between 500°C to 700°C, with a sensitivity peak at about 625°C, consistent with the theoretical predictions of the acoustoelectric effect.

  16. Imaging of oxygen in microreactors and microfluidic systems

    NASA Astrophysics Data System (ADS)

    Sun, Shiwen; Ungerböck, Birgit; Mayr, Torsten

    2015-09-01

    This review gives an overview on the state-of-the-art of oxygen imaging in microfluidics. Oxygen imaging using optical oxygen sensors based on luminescence is a versatile and powerful tool for obtaining profoundly space-resolved information of oxygen in microreactors and microfluidic systems. We briefly introduce the principle of oxygen imaging and present techniques of oxygen imaging applied in microreactors and microfluidic devices, including selection criteria and demands of sensing material and basic set-up for a 2D oxygen sensing system. A detailed review of oxygen imaging in microreactors and microfluidic systems is given on different applications in oxygen gradient monitoring, cell culturing, single-cell analysis and chemical reactions. Finally, we discuss challenges and trends of oxygen imaging in microfluidic systems.

  17. Differentiation of carbon dioxide-sensing neurons in Caenorhabditis elegans requires the ETS-5 transcription factor.

    PubMed

    Guillermin, Manon L; Castelletto, Michelle L; Hallem, Elissa A

    2011-12-01

    Many animals sense environmental gases such as carbon dioxide and oxygen using specialized populations of gas-sensing neurons. The proper development and function of these neurons is critical for survival, as the inability to respond to changes in ambient carbon dioxide and oxygen levels can result in reduced neural activity and ultimately death. Despite the importance of gas-sensing neurons for survival, little is known about the developmental programs that underlie their formation. Here we identify the ETS-family transcription factor ETS-5 as critical for the normal differentiation of the carbon dioxide-sensing BAG neurons in Caenorhabditis elegans. Whereas wild-type animals show acute behavioral avoidance of carbon dioxide, ets-5 mutant animals do not respond to carbon dioxide. The ets-5 gene is expressed in BAG neurons and is required for the normal expression of the BAG neuron gene battery. ets-5 may also autoregulate its expression in BAG neurons. ets-5 is not required for BAG neuron formation, indicating that it is specifically involved in BAG neuron differentiation and the maintenance of BAG neuron cell fate. Our results demonstrate a novel role for ETS genes in the development and function of gas-detecting sensory neurons.

  18. Oxygen safety

    MedlinePlus

    ... with electric motors Electric baseboard or space heaters Wood stoves, fireplaces, candles Electric blankets Hairdryers, electric razors, ... Therapy.aspx . Accessed February 9, 2016. National Fire Protection Association. Medical oxygen. Updated July 2013. www.nfpa. ...

  19. Schopenhauer on Sense Perception and Aesthetic Cognition

    ERIC Educational Resources Information Center

    Vandenabeele, Bart

    2011-01-01

    Schopenhauer's account of sense perception contains an acute critique of Kant's theory of cognition. His analysis of the role of the understanding in perception may be closer to Kant's than he conceded, but his physiological analysis of the role of the senses nonetheless proffers a more plausible account than Kant's transcendental conception of…

  20. Cystitis - acute

    MedlinePlus

    Uncomplicated urinary tract infection; UTI - acute cystitis; Acute bladder infection; Acute bacterial cystitis ... cause. Menopause also increases the risk for a urinary tract infection. The following also increase your chances of having ...

  1. 30 CFR 57.8527 - Oxygen-deficiency testing.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Oxygen-deficiency testing. 57.8527 Section 57... Underground Only § 57.8527 Oxygen-deficiency testing. Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency....

  2. 30 CFR 57.8527 - Oxygen-deficiency testing.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Oxygen-deficiency testing. 57.8527 Section 57... Underground Only § 57.8527 Oxygen-deficiency testing. Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency....

  3. 30 CFR 57.8527 - Oxygen-deficiency testing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Oxygen-deficiency testing. 57.8527 Section 57... Underground Only § 57.8527 Oxygen-deficiency testing. Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency....

  4. 30 CFR 57.8527 - Oxygen-deficiency testing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Oxygen-deficiency testing. 57.8527 Section 57... Underground Only § 57.8527 Oxygen-deficiency testing. Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency....

  5. 30 CFR 57.8527 - Oxygen-deficiency testing.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Oxygen-deficiency testing. 57.8527 Section 57... Underground Only § 57.8527 Oxygen-deficiency testing. Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency....

  6. Remote Sensing.

    ERIC Educational Resources Information Center

    Williams, Richard S., Jr.; Southworth, C. Scott

    1983-01-01

    The Landsat Program became the major event of 1982 in geological remote sensing with the successful launch of Landsat 4. Other 1982 remote sensing accomplishments, research, publications, (including a set of Landsat worldwide reference system index maps), and conferences are highlighted. (JN)

  7. Oxygen Saturation Targeting and Bronchopulmonary Dysplasia.

    PubMed

    Darlow, Brian A; Morley, Colin J

    2015-12-01

    Oxygen saturation targeting is widely used in neonatal intensive care, but the optimal target range in very preterm infants has been uncertain and is the subject of recent debate and research. This review briefly discusses the technology of oxygen monitoring and the role of oxygen toxicity in preterm infants. The background to the recent trials of oxygen saturation targeting in acute and continuing care of very preterm infants is reviewed, and the findings and implications of the recent trials, particularly with respect to bronchopulmonary dysplasia, are discussed.

  8. [Acute respiratory distress syndrome].

    PubMed

    Hecker, M; Weigand, M A; Mayer, K

    2012-05-01

    Acute respiratory distress syndrome (ARDS) is the clinical manifestation of an acute lung injury caused by a variety of direct and indirect injuries to the lung. The cardinal clinical feature of ARDS, refractory arterial hypoxemia, is the result of protein-rich alveolar edema with impaired surfactant function, due to vascular leakage and dysfunction with consequently impaired matching of ventilation to perfusion. Better understanding of the pathophysiology of ARDS has led to the development of novel therapies, pharmacological strategies, and advances in mechanical ventilation. However, protective ventilation is the only confirmed option in ARDS management improving survival, and few other therapies have translated into improved oxygenation or reduced ventilation time. The development of innovative therapy options, such as extracorporeal membrane oxygenation, have the potential to further improve survival of this devastating disease.

  9. Hydrallazine alone in acute left ventricular failure

    PubMed Central

    Clark, A. J. L.; McMichael, H. B.

    1981-01-01

    A patient presented with severe acute left ventricular failure and was treated with hydrallazine and oxygen alone. He made a rapid and full recovery as judged by clinical, radiological and blood gas evidence. ImagesFig. 1 PMID:7329902

  10. Mechanisms of action of hyperbaric oxygenation in stroke: a review.

    PubMed

    Sánchez, Ernesto Cuauhtémoc

    2013-01-01

    This article outlines the therapeutic mechanisms of hyperbaric oxygenation in acute stroke, based on information obtained from peer-reviewed medical literature. Hyperbaric oxygen is an approved treatment modality for ischemia-reperfusion injury in several conditions. It maintains the viability of the marginal tissue, reduces the mitochondrial dysfunction, metabolic penumbra, and blocks inflammatory cascades observed in acute stroke. Basic and clinical data suggest that hyperbaric oxygen could be a safe and effective treatment option in the management of acute stroke. Further work is needed to clarify its clinical utility when applied within the treatment window of "gold standard" treatments (<3-5 hours).

  11. Oxygen and Cell Fate Decisions

    DTIC Science & Technology

    2009-05-27

    2001; Jaakkola et al. 2001) and is targeted by the von Hippel-Lindau ( VHL ) protein for ubiquitination and proteosome-mediated degradation (Maxwell...2001. HIFα targeted for VHL -mediated destruction by proline hydroxylation: implications for O2 sensing. Science, 292:464–8. Ivanovic, Z., Bartolozzi...C.W., Maher, E.R. and Ratcliffe, P.J. 1999. The tumour suppressor protein VHL targets hypoxia-inducible factors for oxygen-dependent proteolysis

  12. Reversible Oxygenation of Oxygen Transport Proteins.

    ERIC Educational Resources Information Center

    Drain, C. M.; Corden, Barry B.

    1987-01-01

    Describes a lecture demonstration which illustrates changes in the visible spectra of oxygen transport proteins upon reversible oxygen binding. Provides a comparison of the physical characteristics of oxygen storage and transport proteins. Reviews essentials for preparation of the materials. (ML)

  13. Acute Bronchitis

    MedlinePlus

    ... can also cause acute bronchitis. To diagnose acute bronchitis, your health care provider will ask about your symptoms and listen to your breathing. You may also have other tests. Treatments include rest, fluids, and aspirin (for adults) or ...

  14. Method of detecting oxygen partial pressure and oxygen partial pressure sensor

    SciTech Connect

    Dees, D.W.

    1991-12-31

    This invention is comprised of a method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured.

  15. Numbers Sense

    ERIC Educational Resources Information Center

    Kathotia, Vinay

    2009-01-01

    This article reports on work undertaken by schools as part of Qualifications and Curriculum Authority's (QCA's) "Engaging mathematics for all learners" project. The goal was to use in the classroom, materials and approaches from a Royal Institution (Ri) Year 10 master-class, "Number Sense", which was inspired by examples from…

  16. Pervasive sensing

    NASA Astrophysics Data System (ADS)

    Nagel, David J.

    2000-11-01

    The coordinated exploitation of modern communication, micro- sensor and computer technologies makes it possible to give global reach to our senses. Web-cameras for vision, web- microphones for hearing and web-'noses' for smelling, plus the abilities to sense many factors we cannot ordinarily perceive, are either available or will be soon. Applications include (1) determination of weather and environmental conditions on dense grids or over large areas, (2) monitoring of energy usage in buildings, (3) sensing the condition of hardware in electrical power distribution and information systems, (4) improving process control and other manufacturing, (5) development of intelligent terrestrial, marine, aeronautical and space transportation systems, (6) managing the continuum of routine security monitoring, diverse crises and military actions, and (7) medicine, notably the monitoring of the physiology and living conditions of individuals. Some of the emerging capabilities, such as the ability to measure remotely the conditions inside of people in real time, raise interesting social concerns centered on privacy issues. Methods for sensor data fusion and designs for human-computer interfaces are both crucial for the full realization of the potential of pervasive sensing. Computer-generated virtual reality, augmented with real-time sensor data, should be an effective means for presenting information from distributed sensors.

  17. Oxygen, gastrin-releasing Peptide, and pediatric lung disease: life in the balance.

    PubMed

    Sunday, Mary E

    2014-01-01

    Excessive oxygen (O2) can cause tissue injury, scarring, aging, and even death. Our laboratory is studying O2-sensing pulmonary neuroendocrine cells (PNECs) and the PNEC-derived product gastrin-releasing peptide (GRP). Reactive oxygen species (ROS) generated from exposure to hyperoxia, ozone, or ionizing radiation (RT) can induce PNEC degranulation and GRP secretion. PNEC degranulation is also induced by hypoxia, and effects of hypoxia are mediated by free radicals. We have determined that excessive GRP leads to lung injury with acute and chronic inflammation, leading to pulmonary fibrosis (PF), triggered via ROS exposure or by directly treating mice with exogenous GRP. In animal models, GRP-blockade abrogates lung injury, inflammation, and fibrosis. The optimal time frame for GRP-blockade and the key target cell types remain to be determined. The concept of GRP as a mediator of ROS-induced tissue damage represents a paradigm shift about how O2 can cause injury, inflammation, and fibrosis. The host PNEC response in vivo may depend on individual ROS sensing mechanisms and subsequent GRP secretion. Ongoing scientific and clinical investigations promise to further clarify the molecular pathways and clinical relevance of GRP in the pathogenesis of diverse pediatric lung diseases.

  18. Conversational sensing

    NASA Astrophysics Data System (ADS)

    Preece, Alun; Gwilliams, Chris; Parizas, Christos; Pizzocaro, Diego; Bakdash, Jonathan Z.; Braines, Dave

    2014-05-01

    Recent developments in sensing technologies, mobile devices and context-aware user interfaces have made it pos- sible to represent information fusion and situational awareness for Intelligence, Surveillance and Reconnaissance (ISR) activities as a conversational process among actors at or near the tactical edges of a network. Motivated by use cases in the domain of Company Intelligence Support Team (CoIST) tasks, this paper presents an approach to information collection, fusion and sense-making based on the use of natural language (NL) and controlled nat- ural language (CNL) to support richer forms of human-machine interaction. The approach uses a conversational protocol to facilitate a ow of collaborative messages from NL to CNL and back again in support of interactions such as: turning eyewitness reports from human observers into actionable information (from both soldier and civilian sources); fusing information from humans and physical sensors (with associated quality metadata); and assisting human analysts to make the best use of available sensing assets in an area of interest (governed by man- agement and security policies). CNL is used as a common formal knowledge representation for both machine and human agents to support reasoning, semantic information fusion and generation of rationale for inferences, in ways that remain transparent to human users. Examples are provided of various alternative styles for user feedback, including NL, CNL and graphical feedback. A pilot experiment with human subjects shows that a prototype conversational agent is able to gather usable CNL information from untrained human subjects.

  19. Towards an optoelectronic luminescent sensing device

    NASA Astrophysics Data System (ADS)

    Papkovsky, Dmitry B.; Ponomarev, Gely V.; Ogurtsov, Vladimir I.; Dvornikov, Alexey A.

    1994-02-01

    The new dye which has improved spectral characteristics synthesized on the basis of platinum complex of the porphyrin-like compound was studied with the view of its application to oxygen sensing. It resulted in a new solid-state oxygen-sensitive material with advanced working characteristics which is highly compatible with excitation with yellow LEDs. This new sensing material makes it possible to develop simple fiber-optoelectronic devices -- prototype oxygen sensors. One of the embodiments was constructed which utilizes powerful yellow LED as a light source, silicone photodiode as a photodetector, and has a fiber-optic output terminated with an active element (oxygen membrane). The electronic scheme of the device provides modulation of LED at a kilohertz range frequency and is capable of measuring specific luminescent signal. The system is now under improvement and optimization with emphasis to lifetime measurements performed by phase method.

  20. Oxygen Flow Rate Requirements of Critically Injured Patients

    DTIC Science & Technology

    2015-04-08

    Military Med. 2013; 178(10):1121-1125. 4. Cabello JB, Burls A, Emparanza JI, Bayliss S, Quinn T. Oxygen therapy for acute myocardial infarction ...Simmonds M, Weatherall M, Beasley R. Routine use of oxygen in the treatment of myocardial infarction : systematic review. Heart. 2009; 95(3):198-202

  1. Portable optical oxygen sensor based on time-resolved fluorescence.

    PubMed

    Chu, Cheng-Shane; Chu, Ssu-Wei

    2014-11-10

    A new, simple signal processing, low-cost technique for the fabrication of a portable oxygen sensor based on time-resolved fluorescence is described. The sensing film uses the oxygen sensing dye platinum meso-tetra (pentfluorophenyl) porphyrin (PtTFPP) embedded in a polymer matrix. The ratio τ0100 measures sensitivity of the sensing film, where τ0 and τ100 represent the detected fluorescence lifetimes from the sensing film exposed to 100% nitrogen and 100% oxygen, respectively. The experimental results reveal that the PtTFPP-doped oxygen sensor has a sensitivity of 2.2 in the 0%-100% range. A preparation procedure for coating the photodiodes with the oxygen sensor film that produces repetitive and reliable sensing devices is proposed. The developed time-resolved optical oxygen sensor is portable, low-cost, has simple signal processing, and lacks optical filter elements. It is a cost-effective alternative to traditional electrochemical-based oxygen sensors and provides a platform for other optical based sensors.

  2. HORIZON SENSING

    SciTech Connect

    Larry G. Stolarczyk

    2003-03-18

    With the aid of a DOE grant (No. DE-FC26-01NT41050), Stolar Research Corporation (Stolar) developed the Horizon Sensor (HS) to distinguish between the different layers of a coal seam. Mounted on mining machine cutter drums, HS units can detect or sense the horizon between the coal seam and the roof and floor rock, providing the opportunity to accurately mine the section of the seam most desired. HS also enables accurate cutting of minimum height if that is the operator's objective. Often when cutting is done out-of-seam, the head-positioning function facilitates a fixed mining height to minimize dilution. With this technology, miners can still be at a remote location, yet cut only the clean coal, resulting in a much more efficient overall process. The objectives of this project were to demonstrate the feasibility of horizon sensing on mining machines and demonstrate that Horizon Sensing can allow coal to be cut cleaner and more efficiently. Stolar's primary goal was to develop the Horizon Sensor (HS) into an enabling technology for full or partial automation or ''agile mining''. This technical innovation (R&D 100 Award Winner) is quickly demonstrating improvements in productivity and miner safety at several prominent coal mines in the United States. In addition, the HS system can enable the cutting of cleaner coal. Stolar has driven the HS program on the philosophy that cutting cleaner coal means burning cleaner coal. The sensor, located inches from the cutting bits, is based upon the physics principles of a Resonant Microstrip Patch Antenna (RMPA). When it is in proximity of the rock-coal interface, the RMPA impedance varies depending on the thickness of uncut coal. The impedance is measured by the computer-controlled electronics and then sent by radio waves to the mining machine. The worker at the machine can read the data via a Graphical User Interface, displaying a color-coded image of the coal being cut, and direct the machine appropriately. The Horizon Sensor

  3. Hyperbaric oxygen therapy. Promoting healing in difficult cases

    SciTech Connect

    Cohn, G.H.

    1986-02-01

    Inhalation of pressurized 100% oxygen is a helpful adjunctive treatment for certain patients, because the increased oxygen carried by the blood to the tissue enhances new growth of microcirculation and, thus, healing. Patients with tissue breakdown after radiation therapy, refractory osteomyelitis, gas gangrene, soft-tissue infection with necrosis from mixed aerobic and anaerobic organisms, crush injuries resulting in acute ischemia, and compromised skin grafts or non-healing wounds are likely to benefit from hyperbaric oxygen therapy.

  4. NO.sub.x sensing devices having conductive oxide electrodes

    DOEpatents

    Montgomery, Frederick C.; West, David L.; Armstrong, Timothy R.; Maxey, Lonnie C.

    2010-03-16

    A NO.sub.x sensing device includes at least one pair of spaced electrodes, at least one of which is made of a conductive oxide, and an oxygen-ion conducting material in bridging electrical communication with the electrodes.

  5. Home Oxygen Therapy

    MedlinePlus

    ... oxygen is rarely delivered in the older large, steel gas cylinders any longer since frequent and costly ... just like the compressed oxygen in the older steel cylinders. An important advantage of liquid oxygen is ...

  6. Active rehabilitation in a pediatric extracorporeal membrane oxygenation patient.

    PubMed

    Zebuhr, Carleen; Sinha, Amit; Skillman, Heather; Buckvold, Shannon

    2014-05-01

    Decreased intensive care unit (ICU) mortality has led to an increase in ICU morbidity. ICU-induced immobilization plays a major role in this morbidity. Recently, ICU mobility has been shown to be safe and effective in adolescent and adult patients. We report the successful rehabilitation of an 8-year-old boy with severe acute respiratory distress syndrome on extracorporeal membrane oxygenation. A child who is critically ill may safely perform active rehabilitation while on venovenous extracorporeal membrane oxygenation. The gains achieved through active rehabilitation and optimal nutrition can facilitate recovery from severe acute respiratory distress syndrome in select pediatric patients on extracorporeal membrane oxygenation.

  7. Surface acoustic wave devices for harsh environment wireless sensing

    DOE PAGES

    Greve, David W.; Chin, Tao -Lun; Zheng, Peng; ...

    2013-05-24

    In this study, langasite surface acoustic wave devices can be used to implement harsh environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensormore » with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.« less

  8. Surface acoustic wave devices for harsh environment wireless sensing

    SciTech Connect

    Greve, David W.; Chin, Tao -Lun; Zheng, Peng; Ohodnicki, Paul; Baltrus, John; Oppenheim, Irving J.

    2013-05-24

    In this study, langasite surface acoustic wave devices can be used to implement harsh environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensor with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.

  9. Surface Acoustic Wave Devices for Harsh Environment Wireless Sensing

    PubMed Central

    Greve, David W.; Chin, Tao-Lun; Zheng, Peng; Ohodnicki, Paul; Baltrus, John; Oppenheim, Irving J.

    2013-01-01

    Langasite surface acoustic wave devices can be used to implement harsh-environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensor with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity. PMID:23708273

  10. Acute Pancreatitis and Pregnancy

    MedlinePlus

    ... Pancreatitis Acute Pancreatitis and Pregnancy Acute Pancreatitis and Pregnancy Timothy Gardner, MD Acute pancreatitis is defined as ... pancreatitis in pregnancy. Reasons for Acute Pancreatitis and Pregnancy While acute pancreatitis is responsible for almost 1 ...

  11. Monitoring Intracellular Oxygen Concentration: Implications for Hypoxia Studies and Real-Time Oxygen Monitoring.

    PubMed

    Potter, Michelle; Badder, Luned; Hoade, Yvette; Johnston, Iain G; Morten, Karl J

    2016-01-01

    The metabolic properties of cancer cells have been widely accepted as a hallmark of cancer for a number of years and have shown to be of critical importance in tumour development. It is generally accepted that tumour cells exhibit a more glycolytic phenotype than normal cells. In this study, we investigate the bioenergetic phenotype of two widely used cancer cell lines, RD and U87MG, by monitoring intracellular oxygen concentrations using phosphorescent Pt-porphyrin based intracellular probes. Our study demonstrates that cancer cell lines do not always exhibit an exclusively glycolytic phenotype. RD demonstrates a reliance on oxidative phosphorylation whilst U87MG display a more glycolytic phenotype. Using the intracellular oxygen sensing probe we generate an immediate readout of intracellular oxygen levels, with the glycolytic lines reflecting the oxygen concentration of the environment, and cells with an oxidative phenotype having significantly lower levels of intracellular oxygen. Inhibition of oxygen consumption in lines with high oxygen consumption increases intracellular oxygen levels towards environmental levels. We conclude that the use of intracellular oxygen probes provides a quantitative assessment of intracellular oxygen levels, allowing the manipulation of cellular bioenergetics to be studied in real time.

  12. The oxygen therapy.

    PubMed

    Corsonello, A; Pedone, C; Scarlata, S; Zito, A; Laino, I; Antonelli-Incalzi, R

    2013-01-01

    Oxygen (O(2)) is a vital element. Shortage of O(2) results in deranged metabolism and important changes in vascular tone with opposite effects on the systemic and pulmonary circulation. During hypoxemia, oxidative stress exposes the organism to a sort of accelerated senescence as well as to several acute untoward effects. Thus, hypoxemia should be promptly recognized and treated, hopefully by measures tailored to the pathophysiological mechanisms underlying hypoxemia. However, O(2) therapy remains the most common therapy of hypoxemia, but it must be carefully tailored to relieve hypoxemia without provoking hyperoxia or hypercarbia. Then, the individual response to O(2) as well as changing needs of O(2) during sleep or exercise must be evaluated to provide the best O(2) therapy. Hyperoxia, the effect of overcorrection of hypoxia, can dramatically impact the health status and threaten the survival of the newborn and, through different mechanisms and effects, the adult. A thorough knowledge of the pathophysiological bases of hypoxemia and O(2) storage and delivery devices is then mandatory to administer O(2) therapy guaranteeing for optimal correction of hypoxemia and minimizing the risk of hyperoxia. Consistent with this aim also is a careful scrutiny of instruments and procedures for monitoring the individual response to O(2) over time. Thus, at variance from classical pharmacological therapy, performing O(2) therapy requires a vast array of clinical and technical competences. The optimal integration of these competences is needed to optimize O(2) therapy on individual bases.

  13. Acute silicosis with bilateral pneumothorax.

    PubMed

    Srivastava, G N; Prasad, Rajniti; Meena, Manoj; Hussain, Moosa

    2014-05-26

    We present a case of acute silicosis with bilateral pneumothorax of a 28-year-old man working at a stone crusher factory for 1 year. He presented to the emergency department with cough, respiratory distress and diffuse chest pain. The patient was managed with bilateral intercostal tube drainage under water seal, oxygen inhalation and conservative therapy. On follow-up he showed improvement of resting dyspnoea and was doing well. This case is being reported because of the rare complications of acute silicosis as bilateral pneumothorax.

  14. Fully Enzymatic Membraneless Glucose|Oxygen Fuel Cell That Provides 0.275 mA cm(-2) in 5 mM Glucose, Operates in Human Physiological Solutions, and Powers Transmission of Sensing Data.

    PubMed

    Ó Conghaile, Peter; Falk, Magnus; MacAodha, Domhnall; Yakovleva, Maria E; Gonaus, Christoph; Peterbauer, Clemens K; Gorton, Lo; Shleev, Sergey; Leech, Dónal

    2016-02-16

    Coimmobilization of pyranose dehydrogenase as an enzyme catalyst, osmium redox polymers [Os(4,4'-dimethoxy-2,2'-bipyridine)2(poly(vinylimidazole))10Cl](+) or [Os(4,4'-dimethyl-2,2'-bipyridine)2(poly(vinylimidazole))10Cl](+) as mediators, and carbon nanotube conductive scaffolds in films on graphite electrodes provides enzyme electrodes for glucose oxidation. The recombinant enzyme and a deglycosylated form, both expressed in Pichia pastoris, are investigated and compared as biocatalysts for glucose oxidation using flow injection amperometry and voltammetry. In the presence of 5 mM glucose in phosphate-buffered saline (PBS) (50 mM phosphate buffer solution, pH 7.4, with 150 mM NaCl), higher glucose oxidation current densities, 0.41 mA cm(-2), are obtained from enzyme electrodes containing the deglycosylated form of the enzyme. The optimized glucose-oxidizing anode, prepared using deglycosylated enzyme coimmobilized with [Os(4,4'-dimethyl-2,2'-bipyridine)2(poly(vinylimidazole))10Cl](+) and carbon nanotubes, was coupled with an oxygen-reducing bilirubin oxidase on gold nanoparticle dispersed on gold electrode as a biocathode to provide a membraneless fully enzymatic fuel cell. A maximum power density of 275 μW cm(-2) is obtained in 5 mM glucose in PBS, the highest to date under these conditions, providing sufficient power to enable wireless transmission of a signal to a data logger. When tested in whole human blood and unstimulated human saliva maximum power densities of 73 and 6 μW cm(-2) are obtained for the same fuel cell configuration, respectively.

  15. [Acute pancreatitis].

    PubMed

    Hecker, M; Mayer, K; Askevold, I; Collet, P; Weigand, M A; Krombach, G A; Padberg, W; Hecker, A

    2014-03-01

    Acute pancreatitis is a potentially fatal disease with individually differing expression of systemic involvement. For this reason early diagnosis with subsequent risk stratification is essential in the clinical management of this frequent gastroenterological disorder. Severe forms of acute pancreatitis occur in approximately 20 % of cases often requiring intensive care monitoring and interdisciplinary therapeutic approaches. In the acute phase adequate fluid replacement and sufficient analgesic therapy is of major therapeutic importance. Concerning the administration of antibiotics and the nutritional support of patients with acute pancreatitis a change in paradigms could be observed in recent years. Furthermore, endoscopic, radiological or surgical interventions can be necessary depending on the severity of the disease and potential complications.

  16. Bronchitis - acute

    MedlinePlus

    ... to breathe. Other symptoms of bronchitis are a cough and coughing up mucus. Acute means the symptoms ... diagnosed with chronic bronchitis, you must have a cough with mucus on most days for at least ...

  17. Acute Bronchitis

    MedlinePlus

    ... bronchitis? Acute bronchitis is inflammation of your bronchial tree. The bronchial tree consists of tubes that carry air into your ... weeks or months. This happens because the bronchial tree takes a while to heal. A lasting cough ...

  18. Bimodular high temperature planar oxygen gas sensor

    PubMed Central

    Sun, Xiangcheng; Liu, Yixin; Gao, Haiyong; Gao, Pu-Xian; Lei, Yu

    2014-01-01

    A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs) thin film coated yttria-stabilized zirconia (YSZ) substrate. The thin film was prepared by radio frequency (r.f.) magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO NPs film was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). X-ray diffraction (XRD) patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500, 600, and 800°C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF) output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors. PMID:25191652

  19. Artificial oxygen transport protein

    DOEpatents

    Dutton, P. Leslie

    2014-09-30

    This invention provides heme-containing peptides capable of binding molecular oxygen at room temperature. These compounds may be useful in the absorption of molecular oxygen from molecular oxygen-containing atmospheres. Also included in the invention are methods for treating an oxygen transport deficiency in a mammal.

  20. Propagation Limitations in Remote Sensing.

    DTIC Science & Technology

    Contents: Multi-sensors and systems in remote sensing ; Radar sensing systems over land; Remote sensing techniques in oceanography; Influence of...propagation media and background; Infrared techniques in remote sensing ; Photography in remote sensing ; Analytical studies in remote sensing .

  1. Fluorescence decay time measurement - a new optical sensing scheme

    NASA Astrophysics Data System (ADS)

    Draxler, Sonja; Lippitsch, Max E.

    1994-02-01

    Optical sensors often suffer from poor long-term stability. This drawback can be overcome by using fluorescence decay-time measurement as the sensing principle. In this way calibration- free chemical sensors can be developed. The sensing scheme has been used so far mainly in connection with dynamic quenching, for example in oxygen sensors. We have succeeded in extending it to ground-state indicator-analyte reactions, thus obtaining stable optical sensors for decay-time sensing of various analytes.

  2. Surface studies of gas sensing metal oxides.

    PubMed

    Batzill, Matthias; Diebold, Ulrike

    2007-05-21

    The relation of surface science studies of single crystal metal oxides to gas sensing applications is reviewed. Most metal oxide gas sensors are used to detect oxidizing or reducing gases and therefore this article focuses on surface reduction processes and the interaction of oxygen with these surfaces. The systems that are discussed are: (i) the oxygen vacancy formation on the surface of the ion conductor CeO(2)(111); (ii) interaction of oxygen with TiO(2) (both adsorption processes and the incorporation of oxygen into the TiO(2)(110) lattice are discussed); (iii) the varying surface composition of SnO(2)(101) and its consequence for the adsorption of water; and (iv) Cu modified ZnO(0001)-Zn surfaces and its interaction with oxygen. These examples are chosen to give a comprehensive overview of surface science studies of different kinds of gas sensing materials and to illustrate the potential that surface science studies have to give fundamental insight into gas sensing phenomena.

  3. S-nitrosylation: integrator of cardiovascular performance and oxygen delivery.

    PubMed

    Haldar, Saptarsi M; Stamler, Jonathan S

    2013-01-01

    Delivery of oxygen to tissues is the primary function of the cardiovascular system. NO, a gasotransmitter that signals predominantly through protein S-nitrosylation to form S-nitrosothiols (SNOs) in target proteins, operates coordinately with oxygen in mammalian cellular systems. From this perspective, SNO-based signaling may have evolved as a major transducer of the cellular oxygen-sensing machinery that underlies global cardiovascular function. Here we review mechanisms that regulate S-nitrosylation in the context of its essential role in "systems-level" control of oxygen sensing, delivery, and utilization in the cardiovascular system, and we highlight examples of aberrant S-nitrosylation that may lead to altered oxygen homeostasis in cardiovascular diseases. Thus, through a bird's-eye view of S-nitrosylation in the cardiovascular system, we provide a conceptual framework that may be broadly applicable to the functioning of other cellular systems and physiological processes and that illuminates new therapeutic promise in cardiovascular medicine.

  4. Vitreal Oxygenation in Retinal Ischemia Reperfusion

    PubMed Central

    Abdallah, Walid; Ameri, Hossein; Barron, Ernesto; Chader, Gerald J.; Greenbaum, Elias; Hinton, David R.

    2011-01-01

    Purpose. To study the feasibility of anterior vitreal oxygenation for the treatment of acute retinal ischemia. Methods. Twenty rabbits were randomized into an oxygenation group, a sham treatment group, and a no treatment group. Baseline electroretinography (ERG) and preretinal oxygen (Po2) measurements were obtained 3 to 5 days before surgery. Intraocular pressure was raised to 100 mm Hg for 90 minutes and then normalized. The oxygenation group underwent vitreal oxygenation for 30 minutes using intravitreal electrodes. The sham treatment group received inactive electrodes for 30 minutes while there was no intervention for the no treatment group. Preretinal Po2 in the posterior vitreous was measured 30 minutes after intervention or 30 minutes after reperfusion (no treatment group) and on postoperative days (d) 3, 6, 9, and 12. On d14, rabbits underwent ERG and were euthanatized. Results. Mean final (d12) Po2 was 10.64 ± 0.77 mm Hg for the oxygenation group, 2.14 ± 0.61 mm Hg for the sham group, and 1.98 ± 0.63 mm Hg for the no treatment group. On ERG, scotopic b-wave amplitude was significantly preserved in the oxygenation group compared with the other two groups. Superoxide dismutase assay showed higher activity in the operated eyes than in the nonoperated control eyes in the sham treatment group and no treatment group only. Histopathology showed preservation of retinal architecture and choroidal vasculature in the oxygenation group, whereas the sham-treated and nontreated groups showed retinal thinning and choroidal atrophy. Conclusions. In severe total ocular ischemia, anterior vitreal oxygenation supplies enough oxygen to penetrate the retinal thickness, resulting in rescue of the RPE/choriocapillaris that continues to perfuse, hence sparing the retinal tissue from damage. PMID:21051734

  5. Oxygen chemisorption cryogenic refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1987-01-01

    The present invention relates to a chemisorption compressor cryogenic refrigerator which employs oxygen to provide cooling at 60 to 100 K. The invention includes dual vessels containing an oxygen absorbent material, alternately heated and cooled to provide a continuous flow of high pressure oxygen, multiple heat exchangers for precooling the oxygen, a Joule-Thomson expansion valve system for expanding the oxygen to partially liquefy it and a liquid oxygen pressure vessel. The primary novelty is that, while it was believed that once oxygen combined with an element or compound the reaction could not reverse to release gaseous oxygen, in this case oxygen will indeed react in a reversible fashion with certain materials and will do so at temperatures and pressures which make it practical for incorporation into a cryogenic refrigeration system.

  6. Electrochemical Oxygen Sensor Development for Liquid Sodium

    NASA Astrophysics Data System (ADS)

    Nollet, Billy K.

    Safe operation of a sodium-cooled fast reactor (SFR) requires in-depth understanding of the corrosion implications of liquid sodium coolant on reactor materials. Dissolved oxygen concentration is of particular importance in characterizing sodium attack, so an accurate means of measuring and controlling oxygen is crucial. There is significant room for improvement in current oxygen sensing technology, so extensive research has been conducted at the University of Wisconsin-Madison to address this issue. Experimental facilities and electrochemical oxygen sensors have been developed, tested, and analyzed. This research is discussed in detail in this report. The oxygen sensors tested in this research were developed using a yttria stabilized zirconia (YSZ) electrolyte whereas many of the past research in this field was conducted with yttria doped thoria (YDT or YST) electrolytes. Thorium, an alpha emitter, is expensive and increasingly difficult to acquire, so motivation to switch to a new material exists. YSZ is commonly used as the electrolyte for solid oxide fuel cells, and ample data is available for high temperature ionic conduction of this material. While some work has been done with YSZ in oxygen sensors (the automotive field, for example, uses YSZ O2 sensors), research on YSZ sensors in sodium is limited. A thorough study of YSZ-based electrochemical oxygen sensors must include detailed corrosion testing and analysis of YSZ in liquid sodium, careful oxygen sensor development and testing, and finally, a comprehensive analysis of the acquired sensor data. The research presented in this report describes the design and development of an electrochemical oxygen sensor for use in sodium using a YSZ electrolyte through the previously-mentioned steps. The designed sensors were subjected to a series of hypotheses which advance common understanding of oxygen sensor signal. These results were used in conjunction with past research to form reliable conclusions.

  7. Metabolic dynamics in skeletal muscle during acute reduction in blood flow and oxygen supply to mitochondria: in-silico studies using a multi-scale, top-down integrated model.

    PubMed

    Dash, Ranjan K; Li, Yanjun; Kim, Jaeyeon; Beard, Daniel A; Saidel, Gerald M; Cabrera, Marco E

    2008-09-09

    Control mechanisms of cellular metabolism and energetics in skeletal muscle that may become evident in response to physiological stresses such as reduction in blood flow and oxygen supply to mitochondria can be quantitatively understood using a multi-scale computational model. The analysis of dynamic responses from such a model can provide insights into mechanisms of metabolic regulation that may not be evident from experimental studies. For the purpose, a physiologically-based, multi-scale computational model of skeletal muscle cellular metabolism and energetics was developed to describe dynamic responses of key chemical species and reaction fluxes to muscle ischemia. The model, which incorporates key transport and metabolic processes and subcellular compartmentalization, is based on dynamic mass balances of 30 chemical species in both capillary blood and tissue cells (cytosol and mitochondria) domains. The reaction fluxes in cytosol and mitochondria are expressed in terms of a general phenomenological Michaelis-Menten equation involving the compartmentalized energy controller ratios ATP/ADP and NADH/NAD(+). The unknown transport and reaction parameters in the model are estimated simultaneously by minimizing the differences between available in vivo experimental data on muscle ischemia and corresponding model outputs in coupled with the resting linear flux balance constraints using a robust, nonlinear, constrained-based, reduced gradient optimization algorithm. With the optimal parameter values, the model is able to simulate dynamic responses to reduced blood flow and oxygen supply to mitochondria associated with muscle ischemia of several key metabolite concentrations and metabolic fluxes in the subcellular cytosolic and mitochondrial compartments, some that can be measured and others that can not be measured with the current experimental techniques. The model can be applied to test complex hypotheses involving dynamic regulation of cellular metabolism and

  8. Solid state oxygen sensor

    DOEpatents

    Garzon, F.H.; Chung, B.W.; Raistrick, I.D.; Brosha, E.L.

    1996-08-06

    Solid state oxygen sensors are provided with a yttria-doped zirconia as an electrolyte and use the electrochemical oxygen pumping of the zirconia electrolyte. A linear relationship between oxygen concentration and the voltage arising at a current plateau occurs when oxygen accessing the electrolyte is limited by a diffusion barrier. A diffusion barrier is formed herein with a mixed electronic and oxygen ion-conducting membrane of lanthanum-containing perovskite or zirconia-containing fluorite. A heater may be used to maintain an adequate oxygen diffusion coefficient in the mixed conducting layer. 4 figs.

  9. Solid state oxygen sensor

    DOEpatents

    Garzon, Fernando H.; Chung, Brandon W.; Raistrick, Ian D.; Brosha, Eric L.

    1996-01-01

    Solid state oxygen sensors are provided with a yttria-doped zirconia as an electrolyte and use the electrochemical oxygen pumping of the zirconia electrolyte. A linear relationship between oxygen concentration and the voltage arising at a current plateau occurs when oxygen accessing the electrolyte is limited by a diffusion barrier. A diffusion barrier is formed herein with a mixed electronic and oxygen ion-conducting membrane of lanthanum-containing perovskite or zirconia-containing fluorite. A heater may be used to maintain an adequate oxygen diffusion coefficient in the mixed conducting layer.

  10. Clinical use of the hyperbaric oxygen bed

    PubMed Central

    Ashfield, R.; Drew, C. E.

    1969-01-01

    The Vickers hyperbaric oxygen bed is described and details of its use are given in the treatment of 207 patients with a wide variety of clinical conditions. As part of a deliberate policy, a special study was made of its place in the treatment of severe acute myocardial infarction. No major procedural difficulties were encountered. Results are generally encouraging and frequently of dramatic benefit. ImagesFig. 1 PMID:5358379

  11. Factors controlling oxygen utilization.

    PubMed

    Biaglow, John; Dewhirst, Mark; Leeper, Dennis; Burd, Randy; Tuttle, Steve

    2005-01-01

    We demonstrate, theoretically, that oxygen diffusion distance is related to the metabolic rate of tumors (QO2) as well as the oxygen tension. The difference in QO2 rate between tumors can vary by as much as 80-fold. Inhibition of oxygen utilization by glucose or chemical inhibitors can improve the diffusion distance. Combining respiratory inhibitors with increased availability of oxygen will further improve the oxygen diffusion distance for all tumors. A simple means for inhibiting oxygen consumption is the use of glucose (the Crabtree effect). The inhibition of tumor oxygen utilization by glucose occurs in R323OAc mammary carcinoma and 9L glioma cells. However, stimulation of oxygen consumption is observed with glucose in the Q7 hepatoma cell line. MIBG, a known inhibitor of oxygen utilization, blocks oxygen consumption in 9L, but is weakly inhibitory with the Q7. Q7 tumor cells demonstrate an anomalous behavior of glucose and MIBG on oxygen consumption. Our results clearly demonstrate the necessity for comparing effects of different agents on different tumor cells. Generalizations cannot be made with respect to the choice of inhibitor for in vivo use. Our work shows that oxygen consumption also can be inhibited with malonate and chlorosuccinate. These substrates may be effective in vivo, where glucose is low and glutamine is the major substrate. Our results indicate that information about individual tumor substrate-linked metabolic controls may be necessary before attempting to inhibit oxygen utilization in vivo for therapeutic benefit.

  12. Enzymatic Glucose Sensor Compensation for Variations in Ambient Oxygen Concentration

    PubMed Central

    Collier, Bradley B.; McShane, Michael J.

    2014-01-01

    Due to the increasing prevalence of diabetes, research toward painless glucose sensing continues. Oxygen sensitive phosphors with glucose oxidase (GOx) can be used to determine glucose levels indirectly by monitoring oxygen consumption. This is an attractive combination because of its speed and specificity. Packaging these molecules together in “smart materials” for implantation will enable non-invasive glucose monitoring. As glucose levels increase, oxygen levels decrease; consequently, the luminescence intensity and lifetime of the phosphor increase. Although the response of the sensor is dependent on glucose concentration, the ambient oxygen concentration also plays a key role. This could lead to inaccurate glucose readings and increase the risk of hyper- or hypoglycemia. To mitigate this risk, the dependence of hydrogel glucose sensor response on oxygen levels was investigated and compensation methods explored. Sensors were calibrated at different oxygen concentrations using a single generic logistic equation, such that trends in oxygen-dependence were determined as varying parameters in the equation. Each parameter was found to be a function of oxygen concentration, such that the correct glucose calibration equation can be calculated if the oxygen level is known. Accuracy of compensation will be determined by developing an overall calibration, using both glucose and oxygen sensors in parallel, correcting for oxygen fluctuations in real time by intentionally varying oxygen, and calculating the error in actual and predicted glucose levels. While this method was developed for compensation of enzymatic glucose sensors, in principle it can also be implemented with other kinds of sensors utilizing oxidases. PMID:26257458

  13. Extracorporeal gas exchange in acute lung injury: step by step towards expanded indications?

    PubMed Central

    2010-01-01

    Extracorporeal membrane oxygenation (ECMO) is widely accepted as a rescue therapy in patients with acute life-threatening hypoxemia in the course of severe acute respiratory distress syndrome (ARDS). However, possible side effects and complications are considered to limit beneficial outcome effects. Therefore, widening indications with the aim of reducing ventilator induced lung injury (VILI) is still controversial. Consequently, technological progress is an important strategy. Miniaturized ECMO systems are believed to simplify handling and reduce side effects and complications. Mueller and co-workers evaluated such a small-sized device in 60 patients with severe ARDS. They accomplished both the treatment of severe hypoxemia and reduction of VILI, demonstrating feasibility, a moderate rate of severe complications, and a 45% intensive care survival rate. Although neither randomized nor controlled, this study should encourage others to implement such systems in clinical practice. From a strategic perspective, this is another small but useful step towards implementing extracorporeal gas exchange for the prevention of VILI. It is already common sense that the prevention of acute life-threatening hypoxemia usually outweighs the risks of this technique. The next step should be to prove that prevention of life-threatening VILI balances the risks too. PMID:20236482

  14. Extracorporeal gas exchange in acute lung injury: step by step towards expanded indications?

    PubMed

    Dembinski, Rolf; Kuhlen, Ralf

    2010-01-01

    Extracorporeal membrane oxygenation (ECMO) is widely accepted as a rescue therapy in patients with acute life-threatening hypoxemia in the course of severe acute respiratory distress syndrome (ARDS). However, possible side effects and complications are considered to limit beneficial outcome effects. Therefore, widening indications with the aim of reducing ventilator induced lung injury (VILI) is still controversial. Consequently, technological progress is an important strategy. Miniaturized ECMO systems are believed to simplify handling and reduce side effects and complications. Mueller and co-workers evaluated such a small-sized device in 60 patients with severe ARDS. They accomplished both the treatment of severe hypoxemia and reduction of VILI, demonstrating feasibility, a moderate rate of severe complications, and a 45% intensive care survival rate. Although neither randomized nor controlled, this study should encourage others to implement such systems in clinical practice. From a strategic perspective, this is another small but useful step towards implementing extracorporeal gas exchange for the prevention of VILI. It is already common sense that the prevention of acute life-threatening hypoxemia usually outweighs the risks of this technique. The next step should be to prove that prevention of life-threatening VILI balances the risks too.

  15. Social cheating in Pseudomonas aeruginosa quorum sensing.

    PubMed

    Sandoz, Kelsi M; Mitzimberg, Shelby M; Schuster, Martin

    2007-10-02

    In a process termed quorum sensing, bacteria use diffusible chemical signals to coordinate cell density-dependent gene expression. In the human pathogen Pseudomonas aeruginosa, quorum sensing controls hundreds of genes, many of which encode extracellular virulence factors. Quorum sensing is required for P. aeruginosa virulence in animal models. Curiously, quorum sensing-deficient variants, most of which carry a mutation in the gene encoding the central quorum sensing regulator lasR, are frequently isolated from acute and chronic infections. The mechanism for their emergence is not known. Here we provide experimental evidence suggesting that these lasR mutants are social cheaters that cease production of quorum-controlled factors and take advantage of their production by the group. We detected an emerging subpopulation of lasR mutants after approximately 100 generations of in vitro evolution of the P. aeruginosa wild-type strain under culture conditions that require quorum sensing for growth. Under such conditions, quorum sensing appears to impose a metabolic burden on the proliferating bacterial cell, because quorum-controlled genes not normally induced until cessation of growth were highly expressed early in growth, and a defined lasR mutant showed a growth advantage when cocultured with the parent strain. The emergence of quorum-sensing-deficient variants in certain environments is therefore an indicator of high quorum sensing activity of the bacterial population as a whole. It does not necessarily indicate that quorum sensing is insignificant, as has previously been suggested. Thus, novel antivirulence strategies aimed at disrupting bacterial communication may be particularly effective in such clinical settings.

  16. Hyperbaric oxygen therapy

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002375.htm Hyperbaric oxygen therapy To use the sharing features on this page, please enable JavaScript. Hyperbaric oxygen therapy uses a special pressure chamber to increase ...

  17. An oxygen enrichment device for lowlanders ascending to high altitude

    PubMed Central

    2013-01-01

    Background When ascending to the high altitude, people living in low altitude areas will suffer from acute mountain sickness. The aim of this study is to test the hypothesis that whether an oxygen concentration membrane can be made and used to construct a new portable oxygen enrichment device for individuals in acute exposure to the high altitude. Methods The membrane was fabricated using vinylsiloxane rubber, polyphenylene oxide hydrogen silicone polymers, chloroplatinic acid and isopropyl alcohol. The membrane was assembled in a frame and the performance was tested in terms of concentration of oxygen, flow rate of oxygen enriched air, pressure ratio across the membrane and ambient temperature. Furthermore, the oxygen concentration device was constructed using the membrane, a DC fan, vacuum pump and gas buffer. A nonrandomized preliminary field test was conducted, in which eight healthy male subjects were flown to Tibet (Lhasa, 3,700 m). First, subjects wore the oxygen enrichment device and performed an incremental exercise on cycle ergometer. The test included heart rate (HR), saturation of peripheral oxygen (SpO2) and physical work capacity (PWC). Then, after a rest period of 4 hours, the experimental protocol was repeated without oxygen enrichment device. Results The testing showed that the membrane could increase the oxygen concentration by up to 30%. Simulation test indicated that although the performance of the oxygen enrichment device decreased with altitudes, the oxygen concentration could still maintain 28% with flow rate of enriched air 110 cm3/s at 5000 m. The field test showed that higher SpO2, lower HR, and better PWC (measured by the PWC-170) were observed from all the subjects using oxygen enrichment device compared with non-using (P < 0.01). Conclusions We concluded that the new portable oxygen enrichment device would be effective in improving exercise performance when ascending to the high altitude. PMID:24103365

  18. [Thematic Issue: Remote Sensing.

    ERIC Educational Resources Information Center

    Howkins, John, Ed.

    1978-01-01

    Four of the articles in this publication discuss the remote sensing of the Earth and its resources by satellites. Among the topics dealt with are the development and management of remote sensing systems, types of satellites used for remote sensing, the uses of remote sensing, and issues involved in using information obtained through remote…

  19. Helium:oxygen versus air:oxygen noninvasive positive-pressure ventilation in patients exposed to sulfur mustard.

    PubMed

    Ghanei, Mostafa; Rajaeinejad, Mohsen; Motiei-Langroudi, Rouzbeh; Alaeddini, Farshid; Aslani, Jafar

    2011-01-01

    Exposure to sulfur mustard (SM) causes a variety of respiratory symptoms, such as chronic bronchitis and constrictive bronchiolitis. This study assessed the effectiveness of noninvasive positive-pressure ventilation, adjunct with 79:21 helium:oxygen instead of 79:21 air:oxygen, in 24 patients with a previous exposure to SM presenting with acute respiratory failure. Both air:oxygen and helium:oxygen significantly decreased systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse rate, respiratory rate, dyspnea, and increased oxygen saturation (P values: .007, .029, .002, <.001, <.001, <.001, and .002 for air:oxygen, respectively, and <.001, .020, .001, <.001, <.001, <.001, and .002, for helium:oxygen, respectively). Moreover, helium:oxygen more potently improved systolic pressure, mean arterial pressure, pulse rate, respiratory rate, and dyspnea (P values: .012, .048, <.001, <.001, and .012, respectively). The results of our study support the benefit of using helium:oxygen adjunct with noninvasive positive-pressure ventilation in patients exposed to SM with acute respiratory decompensation.

  20. Electrochemical Sensing for a Rapidly Evolving World

    NASA Astrophysics Data System (ADS)

    Mullen, Max Robertson

    This dissertation focuses on three projects involving the development of harsh environment gas sensors. The first project discusses the development of a multipurpose oxygen sensor electrode for use in sealing with the common electrolyte yttria stabilized zirconia. The purpose of the sealing function is to produce an internal reference environment maintained by a metal/metal oxide mixture, a criteria for miniaturization of potentiometric oxygen sensing technology. This sensor measures a potential between the internal reference and a sensing environment. The second project discusses the miniaturization of an oxygen sensor and the fabrication of a more generalized electrochemical sensing platform. The third project discusses the discovery of a new mechanism in the electrochemical sensing of ammonia through molecular recognition and the utilization of a sensor taking advantage of the new mechanism. An initial study involving the development of a microwave synthesized La0.8Sr0.2Al0.9Mn0.1O3 sensor electrode material illustrates the ability of the material developed to meet ionic and electronic conducting requirements for effective and Nernstian oxygen sensing. In addition the material deforms plastically under hot isostatic pressing conditions in a similar temperature and pressure regime with yttria stabilized zirconia to produce a seal and survive temperatures up to 1350 °C. In the second project we show novel methods to seal an oxygen environment inside a device cavity to produce an electrochemical sensor body using room temperature plasma-activated bonding and low temperature and pressure assisted plasma-activated bonding with silicon bodies, both in a clean room environment. The evolution from isostatic hot pressing methods towards room temperature complementary metal oxide semiconductor (CMOS) compatible technologies using single crystal silicon substrates in the clean room allows the sealing of devices on a much larger scale. Through this evolution in bonding

  1. Oxygen control with microfluidics.

    PubMed

    Brennan, Martin D; Rexius-Hall, Megan L; Elgass, Laura Jane; Eddington, David T

    2014-11-21

    Cellular function and behavior are affected by the partial pressure of O2, or oxygen tension, in the microenvironment. The level of oxygenation is important, as it is a balance of oxygen availability and oxygen consumption that is necessary to maintain normoxia. Changes in oxygen tension, from above physiological oxygen tension (hyperoxia) to below physiological levels (hypoxia) or even complete absence of oxygen (anoxia), trigger potent biological responses. For instance, hypoxia has been shown to support the maintenance and promote proliferation of regenerative stem and progenitor cells. Paradoxically, hypoxia also contributes to the development of pathological conditions including systemic inflammatory response, tumorigenesis, and cardiovascular disease, such as ischemic heart disease and pulmonary hypertension. Current methods to study cellular behavior in low levels of oxygen tension include hypoxia workstations and hypoxia chambers. These culture systems do not provide oxygen gradients that are found in vivo or precise control at the microscale. Microfluidic platforms have been developed to overcome the inherent limits of these current methods, including lack of spatial control, slow equilibration, and unachievable or difficult coupling to live-cell microscopy. The various applications made possible by microfluidic systems are the topic of this review. In order to understand how the microscale can be leveraged for oxygen control of cells and tissues within microfluidic systems, some background understanding of diffusion, solubility, and transport at the microscale will be presented in addition to a discussion on the methods for measuring the oxygen tension in microfluidic channels. Finally the various methods for oxygen control within microfluidic platforms will be discussed including devices that rely on diffusion from liquid or gas, utilizing on-or-off-chip mixers, leveraging cellular oxygen uptake to deplete the oxygen, relying on chemical reactions in

  2. Solid state oxygen sensor

    DOEpatents

    Garzon, Fernando H.; Brosha, Eric L.

    1997-01-01

    A potentiometric oxygen sensor is formed having a logarithmic response to a differential oxygen concentration while operating as a Nernstian-type sensor. Very thin films of mixed conducting oxide materials form electrode services while permitting diffusional oxygen access to the interface between the zirconia electrolyte and the electrode. Diffusion of oxygen through the mixed oxide is not rate-limiting. Metal electrodes are not used so that morphological changes in the electrode structure do not occur during extended operation at elevated temperatures.

  3. Oxygen evolution reaction catalysis

    DOEpatents

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  4. Smart oxygen cuvette for optical monitoring of dissolved oxygen in biological blood samples

    NASA Astrophysics Data System (ADS)

    Dabhi, Harish; Alla, Suresh Kumar; Shahriari, Mahmoud R.

    2010-02-01

    A smart Oxygen Cuvette is developed by coating the inner surface of a cuvette with oxygen sensitive thin film material. The coating is glass like sol-gel based sensor that has an embedded ruthenium compound in the glass film. The fluorescence of the ruthenium is quenched depending on the oxygen level. Ocean Optics phase fluorometer, NeoFox is used to measure this rate of fluorescence quenching and computes it for the amount of oxygen present. Multimode optical fibers are used for transportation of light from an LED source to cuvette and from cuvette to phase fluorometer. This new oxygen sensing system yields an inexpensive solution for monitoring the dissolved oxygen in samples for biological and medical applications. In addition to desktop fluorometers, smart oxygen cuvettes can be used with the Ocean Optics handheld Fluorometers, NeoFox Sport. The Smart Oxygen Cuvettes provide a resolution of 4PPB units, an accuracy of less than 5% of the reading, and 90% response in less than 10 seconds.

  5. Acute Pancreatitis

    PubMed Central

    Geokas, Michael C.

    1972-01-01

    For many decades two types of acute pancreatitis have been recognized: the edematous or interstitial and the hemorrhagic or necrotic. In most cases acute pancreatitis is associated with alcoholism or biliary tract disease. Elevated serum or urinary α-amylase is the most important finding in diagnosis. The presence of methemalbumin in serum and in peritoneal or pleural fluid supports the diagnosis of the hemorrhagic form of the disease in patients with a history and enzyme studies suggestive of pancreatitis. There is no characteristic clinical picture in acute pancreatitis, and its complications are legion. Pancreatic pseudocyst is probably the most common and pancreatic abscess is the most serious complication. The pathogenetic principle is autodigestion, but the precise sequence of biochemical events is unclear, especially the mode of trypsinogen activation and the role of lysosomal hydrolases. A host of metabolic derangements have been identified in acute pancreatitis, involving lipid, glucose, calcium and magnesium metabolism and changes of the blood clotting mechanism, to name but a few. Medical treatment includes intestinal decompression, analgesics, correction of hypovolemia and other supportive and protective measures. Surgical exploration is advisable in selected cases, when the diagnosis is in doubt, and is considered imperative in the presence of certain complications, especially pancreatic abscess. PMID:4559467

  6. Oxygen boost pump study

    NASA Technical Reports Server (NTRS)

    1975-01-01

    An oxygen boost pump is described which can be used to charge the high pressure oxygen tank in the extravehicular activity equipment from spacecraft supply. The only interface with the spacecraft is the +06 6.205 Pa supply line. The breadboard study results and oxygen tank survey are summarized and the results of the flight-type prototype design and analysis are presented.

  7. Oxygen sensitive microwells.

    PubMed

    Sinkala, Elly; Eddington, David T

    2010-12-07

    Oxygen tension is critical in a number of cell pathways but is often overlooked in cell culture. One reason for this is the difficulty in modulating and assessing oxygen tensions without disturbing the culture conditions. Toward this end, a simple method to generate oxygen-sensitive microwells was developed through embossing polystyrene (PS) and platinum(ii) octaethylporphyrin ketone (PtOEPK) thin films. In addition to monitoring the oxygen tension, microwells were employed in order to isolate uniform clusters of cells in microwells. The depth and width of the microwells can be adapted to different experimental parameters easily by altering the thin film processing or embossing stamp geometries. The thin oxygen sensitive microwell substrate is also compatible with high magnification modalities such as confocal imaging. The incorporation of the oxygen sensor into the microwells produces measurements of the oxygen tension near the cell surface. The oxygen sensitive microwells were calibrated and used to monitor oxygen tensions of Madin-Darby Canine Kidney Cells (MDCKs) cultured at high and low densities as a proof of concept. Wells 500 µm in diameter seeded with an average of 330 cells exhibited an oxygen level of 12.6% whereas wells seeded with an average of 20 cells per well exhibited an oxygen level of 19.5%, a 35.7% difference. This platform represents a new tool for culturing cells in microwells in a format amenable to high magnification imaging while monitoring the oxygen state of the culture media.

  8. Indicators: Dissolved Oxygen

    EPA Pesticide Factsheets

    Dissolved oxygen (DO) is the amount of oxygen that is present in water. It is an important measure of water quality as it indicates a water body's ability to support aquatic life. Water bodies receive oxygen from the atmosphere and from aquatic plants.

  9. Hypoxemia (Low Blood Oxygen)

    MedlinePlus

    Symptoms Hypoxemia (low blood oxygen) By Mayo Clinic Staff Hypoxemia is a below-normal level of oxygen in your blood, specifically in the arteries. Hypoxemia ... of breath. Hypoxemia is determined by measuring the oxygen level in a blood sample taken from an ...

  10. Acidotoxicity via ASIC1a Mediates Cell Death during Oxygen Glucose Deprivation and Abolishes Excitotoxicity.

    PubMed

    Bhowmick, Saurav; Moore, Jeanette T; Kirschner, Daniel L; Curry, Mary C; Westbrook, Emily G; Rasley, Brian T; Drew, Kelly L

    2017-03-01

    Ischemic reperfusion (I/R) injury is associated with a complex and multifactorial cascade of events involving excitotoxicity, acidotoxicity, and ionic imbalance. While it is known that acidosis occurs concomitantly with glutamate-mediated excitotoxicity during brain ischemia, it remains elusive how acidosis-mediated acidotoxicity interacts with glutamate-mediated excitotoxicity. Here, we investigated the effect of acidosis on glutamate-mediated excitotoxicity in acute hippocampal slices. We tested the hypothesis that mild acidosis protects against I/R injury via modulation of NMDAR, but produces injury via activation of acid sensing ion channels (ASIC1a). Using a novel microperfusion approach, we monitored time course of injury in acutely prepared, adult hippocampal slices. We varied the duration of insult to delay the return to preinsult conditions to determine if injury was caused by the primary insult or by the modeled reperfusion phase. We also manipulated pH in presence and absence of oxygen glucose deprivation (OGD). The role of ASIC1a and NMDAR was deciphered by treating the slices with and without an ASIC or NMDAR antagonist. Our results show that injury due to OGD or low pH occurs during the insult rather than the modeled reperfusion phase. Injury mediated by low pH or low pH OGD requires ASIC1a and is independent of NMDAR activation. These findings point to ASIC1a as a mediator of ischemic cell death caused by stroke and cardiac arrest.

  11. Investigations of new potentiometric gas sensing systems

    SciTech Connect

    Yim, Hyoung-Sik

    1992-01-01

    Research concerning the development of new and/or improved potentiometric gas sensing systems is described. Studies relating to the development of reversible potentiometric oxygen sensors based on polymeric and metallic film electrodes are presented. In addition, the design and analytical utility of a novel differential ion-selective membrane electrode-based potentiometric gas sensing cell with enhanced sensitivity is documented. The performance of a reversible potentiometric oxygen gas sensor based on a polymeric membrane doped with cobalt-complexes is described. For such sensors, the potentiometric oxygen response is attributed to a mixed potential originating from the underlying platinum electrode surface as well as the Co(II)-tetren doped film. This leads to a short term oxygen response of nearly the theoretical slope value of 118 mV/decade, below 10% O[sub 2]. In the presence of the Co(II)-tetren/PVC film, an analytically useful response is observed for approx. 6-8 days. Thin films of metallic copper, electrochemically deposited on platinum and sputtered on a single crystal silicon wafer, are also examined for reversible potentiometric oxygen sensing. The long-term reversibility and potentiometric stability of such copper film-based sensors is enhanced (up to one month) by preventing the formation of cuprous oxide on the surfaces via the application of an external non-polarizing cathodic current through the working electrode, or by specifically using sputtered copper films that have [100] crystal structures as determined by X-ray diffraction. Finally, the development and application of a differential ion-selective membrane electrode-based potentiometric gas sensing cell is described. The prospects of fabricating differential detection arrangements for CO[sub 2], NO[sub 2], and SO[sub 2], NH[sub 3] are also discussed.

  12. Acute administration of 3-nitropropionic acid, a reactive oxygen species generator, boosts ethanol-induced locomotor stimulation. New support for the role of brain catalase in the behavioural effects of ethanol.

    PubMed

    Manrique, Héctor M; Miquel, Marta; Aragon, Carlos M G

    2006-12-01

    The antioxidant enzyme catalase by reacting with H(2)O(2), forms the compound known as compound I (catalase-H(2)O(2)). This compound is able to oxidise ethanol to acetaldehyde in the CNS. It has been demonstrated that 3-nitropropionic acid (3-NPA) induces the activity of the brain catalase-H(2)O(2) system. In this study, we tested the effect of 3-NPA on both the brain catalase-H(2)O(2) system and on the acute locomotor effect of ethanol. To find the optimal interval for the 3-NPA-ethanol interaction mice were treated with 3-NPA 0, 45, 90 and 135min before an ethanol injection (2.4mg/kg). In a second study, 3-NPA (0, 15, 30 or 45mg/kg) was administered SC to animals 90min before saline or several doses of ethanol (1.6 or 2.4g/kg), and the open-field behaviour was registered. The specificity of the effect of 3-NPA (45mg/kg) was evaluated on caffeine (10mg/kg IP) and cocaine (4mg/kg)-induced locomotion. The prevention of 3-NPA effects on both ethanol-induced locomotion and brain catalase activity by L-carnitine, a potent antioxidant, was also studied. Nitropropionic acid boosted ethanol-induced locomotion and brain catalase activity after 90min. The effect of 3-NPA was prevented by l-carnitine administration. These results indicate that 3-NPA enhanced ethanol-induced locomotion by increasing the activity of the brain catalase system.

  13. Clinical review: Extracorporeal membrane oxygenation

    PubMed Central

    2011-01-01

    The H1N1 flu pandemic led to a wider use of extracorporeal membrane oxygenation (ECMO), proving its power in hypoxemic emergencies. The results obtained during this pandemic, more than any randomized trial, led to the worldwide acceptance of the use of membrane lungs. Moreover, as centers that applied this technique as rescue therapy for refractory hypoxemia recognized its strength and limited technical challenges, the indications for ECMO have recently been extended. Indications for veno-venous ECMO currently include respiratory support as a bridge to lung transplantation, correction of lung hyperinflation during chronic obstructive pulmonary disease exacerbation and respiratory support in patients with the acute respiratory distress syndrome, possibly also without mechanical ventilation. The current enthusiasm for ECMO in its various aspects should not, however, obscure the consideration of the potential complications associated with this life-saving technique, primarily brain hemorrhage PMID:22188792

  14. The new experimental areas oxygen monitor

    SciTech Connect

    Schoo, D.

    1988-08-01

    Because of the nature of the beamline requirements for oxygen monitoring equipment to operate ancillary equipment, such as exhaust fans, doors and cryogenic valves, and because of the well known problems of the oxygen sensors installed in high radiation areas, a new design for sensing the oxygen content of ambient air was needed. A new monitor system was designed to solve these problems and some others that compromised the reliability and the maintenance of the monitoring system. From the operating experience gained with the Accelerator Standard Oxygen Monitor System currently installed in many locations in the experimental area, from suggestions solicited from the Safety Group and from the Cryogenics Group, I designed a new Experimental Areas Standard Oxygen Monitor. Many suggestions were carefully considered and a design that incorporates most of them was constructed. I will summarize a list of the important improvements that will be of interest to the users of the system, and explain how these functions will make the oxygen system easier to live with. 2 figs.

  15. Singlet oxygen in photosensitization.

    PubMed

    Moan, Johan; Juzenas, Petras

    2006-01-01

    Oxygen is a ubiquitous element and a vitally important substance for life on the Earth, and especially for human life. Living organisms need oxygen for most, if not all, of their cellular functions. On the other hand, oxygen can produce metabolites that are toxic and potentially lethal to the same cells. Being reactive and chemically unstable reactive oxygen species (ROS) are the most important metabolites that initiate reduction and oxidation (redox) reactions under physiological conditions. Oxygen in its excited singlet state (1O2) is probably the most important intermediate in such reactions. Since the discovery of oxygen by Joseph Priestley in 1775 it has been recognized that oxygen can be both beneficial and harmful to life.

  16. Placental Gas Exchange and the Oxygen Supply to the Fetus.

    PubMed

    Carter, Anthony M

    2015-07-01

    The oxygen supply of the fetus depends on the blood oxygen content and flow rate in the uterine and umbilical arteries and the diffusing capacity of the placenta. Oxygen consumption by the placenta is a significant factor and a potential limitation on availability to the fetus. The relevance of these several factors as well as responses to acute or sustained hypoxia has been explored in the sheep model. In addition, much has been learned in the context of hypobaric hypoxia by studying human populations that have resided at high altitude for varying periods of time. Embryonic development occurs under anaerobic conditions and even the fetus is adapted to a low oxygen environment. Nevertheless, there is a reserve capacity, and during acute hypoxia the fetus can counter a 50% reduction in oxygen delivery by increasing fractional extraction. During sustained hypoxia, on the other hand, fetal growth is slowed, although oxygen consumption is unaltered when corrected for fetal mass. Similarly, birth weight is reduced in humans living at high altitude even if the effect is tempered in those with a long highland ancestry. Placental mass changes little during sustained hypoxia in sheep or humans at high altitude. This conceals the fact that there are structural changes and that placental oxygen consumption is reduced. The underlying mechanisms are a current focus of research. One intriguing possibility is that increased anaerobic metabolism of glucose in the placenta spares oxygen for the fetus but reduces its supply of substrate and thereby limits fetal growth.

  17. A fibre optic oxygen sensor for monitoring of human breathing

    NASA Astrophysics Data System (ADS)

    Chen, Rongsheng; Farmery, Andrew D.; Chen, Rui; Hahn, Clive E. W.

    2011-11-01

    A reliable and cost effective fibre optic oxygen sensor for monitoring of human breathing has been developed using a normal 200μm silica core/silica cladding optical fibre and a polymer sensing matrix. The fibre optic oxygen sensor is based on the fluorescence quenching of a fluorophore by oxygen. The sensing matrix, containing immobilized Pt(II) complexes, was coated at the end of the silica core/silica cladding optical fibre. The sensitivity and time response of the sensor were evaluated using the method of luminescence lifetime measurement. The polymer substrate influence on the time response of the sensor was improved by using a fibre taper design, and the response time of the optimized sensor was less than 200ms. This silica fibre based optic oxygen sensor is suitable for monitoring of patient breathing in intensive care unit in terms of safety and low cost.

  18. Acute Vestibulopathy

    PubMed Central

    Cha, Yoon-Hee

    2011-01-01

    The presentation of acute vertigo may represent both a common benign disorder or a life threatening but rare one. Familiarity with the common peripheral vestibular disorders will allow the clinician to rapidly “rule-in” a benign disorder and recognize when further testing is required. Key features of vertigo required to make an accurate diagnosis are duration, chronicity, associated symptoms, and triggers. Bedside tests that are critical to the diagnosis of acute vertigo include the Dix-Hallpike maneuver and canalith repositioning manuever, occlusive ophthalmoscopy, and the head impulse test. The goal of this review is to provide the clinician with the clinical and pathophysiologic background of the most common disorders that present with vertigo to develop a logical differential diagnosis and management plan. PMID:23983835

  19. Carotid body oxygen sensing and adaptation to hypoxia.

    PubMed

    López-Barneo, José; Macías, David; Platero-Luengo, Aida; Ortega-Sáenz, Patricia; Pardal, Ricardo

    2016-01-01

    The carotid body (CB) is the principal arterial chemoreceptor that mediates the hyperventilatory response to hypoxia. Our understanding of CB function and its role in disease mechanisms has progressed considerably in the last decades, particularly in recent years. The sensory elements of the CB are the neuron-like glomus cells, which contain numerous transmitters and form synapses with afferent sensory fibers. The activation of glomus cells under hypoxia mainly depends on the modulation of O2-sensitive K(+) channels which leads to cell depolarization and the opening of Ca(2+) channels. This model of sensory transduction operates in all mammalian species studied thus far, including man. However, the molecular mechanisms underlying the modulation of ion channel function by changes in the O2 level are as yet unknown. The CB plays a fundamental role in acclimatization to sustained hypoxia. Mice with CB atrophy or patients who have undergone CB resection due to surgical treatments show a marked intolerance to even mild hypoxia. CB growth under hypoxia is supported by the existence of a resident population of neural crest-derived stem cells of glia-like phenotype. These stem cells are not highly affected by exposure to low O2 tension; however, there are abundant synapse-like contacts between the glomus cells and stem cells (chemoproliferative synapses), which may be needed to trigger progenitor cell proliferation and differentiation under hypoxia. CB hypo- or hyper-activation may also contribute to the pathogenesis of several prevalent human diseases.

  20. 42 CFR 414.226 - Oxygen and oxygen equipment.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 3 2012-10-01 2012-10-01 false Oxygen and oxygen equipment. 414.226 Section 414... Durable Medical Equipment and Prosthetic and Orthotic Devices § 414.226 Oxygen and oxygen equipment. (a) Payment rules—(1) Oxygen equipment. Payment for rental of oxygen equipment is made based on a monthly...

  1. 42 CFR 414.226 - Oxygen and oxygen equipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Oxygen and oxygen equipment. 414.226 Section 414... Equipment and Prosthetic and Orthotic Devices § 414.226 Oxygen and oxygen equipment. (a) Payment rules—(1) Oxygen equipment. Payment for rental of oxygen equipment is made based on a monthly fee schedule...

  2. 42 CFR 414.226 - Oxygen and oxygen equipment.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 3 2013-10-01 2013-10-01 false Oxygen and oxygen equipment. 414.226 Section 414... Durable Medical Equipment and Prosthetic and Orthotic Devices § 414.226 Oxygen and oxygen equipment. (a) Payment rules—(1) Oxygen equipment. Payment for rental of oxygen equipment is made based on a monthly...

  3. 42 CFR 414.226 - Oxygen and oxygen equipment.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 3 2014-10-01 2014-10-01 false Oxygen and oxygen equipment. 414.226 Section 414... Durable Medical Equipment, Prosthetic and Orthotic Devices, and Surgical Dressings § 414.226 Oxygen and oxygen equipment. (a) Payment rules—(1) Oxygen equipment. Payment for rental of oxygen equipment is...

  4. 42 CFR 414.226 - Oxygen and oxygen equipment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Oxygen and oxygen equipment. 414.226 Section 414... Equipment and Prosthetic and Orthotic Devices § 414.226 Oxygen and oxygen equipment. (a) Payment rules—(1) Oxygen equipment. Payment for rental of oxygen equipment is made based on a monthly fee schedule...

  5. Acute Blindness.

    PubMed

    Meekins, Jessica M

    2015-09-01

    Sudden loss of vision is an ophthalmic emergency with numerous possible causes. Abnormalities may occur at any point within the complex vision pathway, from retina to optic nerve to the visual center in the occipital lobe. This article reviews specific prechiasm (retina and optic nerve) and cerebral cortical diseases that lead to acute blindness. Information regarding specific etiologies, pathophysiology, diagnosis, treatment, and prognosis for vision is discussed.

  6. [Acute respiratory distress syndrome].

    PubMed

    Matĕjovic, M; Novák, I; Srámek, V; Rokyta, R; Hora, P; Nalos, M

    1999-04-26

    Acute respiratory distress syndrome (ARDS) is the general term used for severe acute respiratory failure of diverse aetiology. It is associated with a high morbidity, mortality (50-70%), and financial costs. Regardless of aetiology, the basic pathogenesis of ARDS is a systemic inflammatory response leading to a diffuse inflammatory process that involves both lungs, thus causing diffuse alveolar and endothelial damage with increased pulmonary capillary permeability and excessive extravascular lung water accumulation. ARDS is commonly associated with sepsis and multiple organ failure. The clinical picture involves progressive hypoxaemia, radiographic evidence of pulmonary oedema, decreased lung compliance and pulmonary hypertension. Despite the scientific and technological progress in critical care medicine, there is no specific ARDS therapy available at the moment and its management remains supportive. Therapeutic goals include resolution of underlying conditions, maintenance of acceptable gas exchange and tissue oxygenation and prevention of iatrogenic lung injury. Many new specific therapeutic strategies have been developed, however, most of them require further scientific evaluation. The paper reviews definition, basic pathogenesis and pathophysiology of ARDS and discusses current concepts of therapeutic possibilities of ARDS.

  7. Luxury perfusion phenomenon in acute herpes simplex virus encephalitis.

    PubMed

    Tanaka, M; Uesugi, M; Igeta, Y; Kondo, S; Sun, X; Hirai, S

    1995-02-01

    In a patient with acute herpes simplex virus (HSV) encephalitis, positron emission tomography (PET) demonstrated increased cerebral blood flow in the affected temporal lobe accompanied by reduction in the cerebral oxygen extraction fraction and the cerebral metabolic rate of oxygen, i.e., luxury perfusion. Follow-up PET studies showed reduction in cerebral perfusion until it was more closely coupled with oxygen metabolism after the resolution of the acute inflammation. These findings support previous single photon emission computed tomographic data and provide a pathophysiological background for the occurrence of hyperperfusion in HSV encephalitis. This is an interesting example of the luxury perfusion phenomenon occurring in a disease other than cerebral ischemia.

  8. Acute exacerbation of COPD.

    PubMed

    Ko, Fanny W; Chan, Ka Pang; Hui, David S; Goddard, John R; Shaw, Janet G; Reid, David W; Yang, Ian A

    2016-10-01

    The literature of acute exacerbation of chronic obstructive pulmonary disease (COPD) is fast expanding. This review focuses on several aspects of acute exacerbation of COPD (AECOPD) including epidemiology, diagnosis and management. COPD poses a major health and economic burden in the Asia-Pacific region, as it does worldwide. Triggering factors of AECOPD include infectious (bacteria and viruses) and environmental (air pollution and meteorological effect) factors. Disruption in the dynamic balance between the 'pathogens' (viral and bacterial) and the normal bacterial communities that constitute the lung microbiome likely contributes to the risk of exacerbations. The diagnostic approach to AECOPD varies based on the clinical setting and severity of the exacerbation. After history and examination, a number of investigations may be useful, including oximetry, sputum culture, chest X-ray and blood tests for inflammatory markers. Arterial blood gases should be considered in severe exacerbations, to characterize respiratory failure. Depending on the severity, the acute management of AECOPD involves use of bronchodilators, steroids, antibiotics, oxygen and noninvasive ventilation. Hospitalization may be required, for severe exacerbations. Nonpharmacological interventions including disease-specific self-management, pulmonary rehabilitation, early medical follow-up, home visits by respiratory health workers, integrated programmes and telehealth-assisted hospital at home have been studied during hospitalization and shortly after discharge in patients who have had a recent AECOPD. Pharmacological approaches to reducing risk of future exacerbations include long-acting bronchodilators, inhaled steroids, mucolytics, vaccinations and long-term macrolides. Further studies are needed to assess the cost-effectiveness of these interventions in preventing COPD exacerbations.

  9. Treatment for acute asthma in the Emergency Department: practical aspects.

    PubMed

    Urso, D L

    2010-03-01

    This article describes the management of acute asthma exacerbation in the Emergency Department (ED). An asthma exacerbation can be defined as clinical worsening of disease or an asymptomatic decrease in peak flows. Acute exacerbations of asthma may represent reactions to airway irritants or failures of chronic treatment. Hospitalizations and ED visits account for a large proportion of the health-care cost burden of asthma. The assessment of an asthma exacerbation constitutes a process with two different dimensions: to determine the severity of attack, and to evaluate the response to treatment. The principal goals of managing an asthma acute exacerbation may be summarized as maintenance of adequate arterial oxygen saturation with supplemental oxygen, relief of airflow obstruction with repetitive administration of short acting beta-2 agonists (SABA), and treatment of airway inflammation with systemic corticosteroids (CS) to prevent future relapses. SABA, oxygen, and CS form the basis of management of acute asthma exacerbation but a role is emerging for anthicolinergics.

  10. Mobile Sensing Systems

    PubMed Central

    Macias, Elsa; Suarez, Alvaro; Lloret, Jaime

    2013-01-01

    Rich-sensor smart phones have made possible the recent birth of the mobile sensing research area as part of ubiquitous sensing which integrates other areas such as wireless sensor networks and web sensing. There are several types of mobile sensing: individual, participatory, opportunistic, crowd, social, etc. The object of sensing can be people-centered or environment-centered. The sensing domain can be home, urban, vehicular… Currently there are barriers that limit the social acceptance of mobile sensing systems. Examples of social barriers are privacy concerns, restrictive laws in some countries and the absence of economic incentives that might encourage people to participate in a sensing campaign. Several technical barriers are phone energy savings and the variety of sensors and software for their management. Some existing surveys partially tackle the topic of mobile sensing systems. Published papers theoretically or partially solve the above barriers. We complete the above surveys with new works, review the barriers of mobile sensing systems and propose some ideas for efficiently implementing sensing, fusion, learning, security, privacy and energy saving for any type of mobile sensing system, and propose several realistic research challenges. The main objective is to reduce the learning curve in mobile sensing systems where the complexity is very high. PMID:24351637

  11. Mobile sensing systems.

    PubMed

    Macias, Elsa; Suarez, Alvaro; Lloret, Jaime

    2013-12-16

    Rich-sensor smart phones have made possible the recent birth of the mobile sensing research area as part of ubiquitous sensing which integrates other areas such as wireless sensor networks and web sensing. There are several types of mobile sensing: individual, participatory, opportunistic, crowd, social, etc. The object of sensing can be people-centered or environment-centered. The sensing domain can be home, urban, vehicular… Currently there are barriers that limit the social acceptance of mobile sensing systems. Examples of social barriers are privacy concerns, restrictive laws in some countries and the absence of economic incentives that might encourage people to participate in a sensing campaign. Several technical barriers are phone energy savings and the variety of sensors and software for their management. Some existing surveys partially tackle the topic of mobile sensing systems. Published papers theoretically or partially solve the above barriers. We complete the above surveys with new works, review the barriers of mobile sensing systems and propose some ideas for efficiently implementing sensing, fusion, learning, security, privacy and energy saving for any type of mobile sensing system, and propose several realistic research challenges. The main objective is to reduce the learning curve in mobile sensing systems where the complexity is very high.

  12. Oxygen ion conducting materials

    DOEpatents

    Vaughey, John; Krumpelt, Michael; Wang, Xiaoping; Carter, J. David

    2005-07-12

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  13. Oxygen ion conducting materials

    DOEpatents

    Carter, J. David; Wang, Xiaoping; Vaughey, John; Krumpelt, Michael

    2004-11-23

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  14. Integrated turbomachine oxygen plant

    SciTech Connect

    Anand, Ashok Kumar; DePuy, Richard Anthony; Muthaiah, Veerappan

    2014-06-17

    An integrated turbomachine oxygen plant includes a turbomachine and an air separation unit. One or more compressor pathways flow compressed air from a compressor through one or more of a combustor and a turbine expander to cool the combustor and/or the turbine expander. An air separation unit is operably connected to the one or more compressor pathways and is configured to separate the compressed air into oxygen and oxygen-depleted air. A method of air separation in an integrated turbomachine oxygen plant includes compressing a flow of air in a compressor of a turbomachine. The compressed flow of air is flowed through one or more of a combustor and a turbine expander of the turbomachine to cool the combustor and/or the turbine expander. The compressed flow of air is directed to an air separation unit and is separated into oxygen and oxygen-depleted air.

  15. Oxygen, a paradoxical element?

    PubMed

    Greabu, Maria; Battino, M; Mohora, Maria; Olinescu, R; Totan, Alexandra; Didilescu, Andreea

    2008-01-01

    Oxygen is an essential element for life on earth. No life may exist without oxygen. But in the last forty years, conclusive evidence demonstrated the double-edge sword of this element. In certain conditions, oxygen may produce reactive species, even free radicals. More, the production of reactive oxygen species (ROS) takes place everywhere: in air, nature or inside human bodies. The paradox of oxygen atom is entirely due to its peculiar electronic structure. But life began on earth, only when nature found efficient weapons against ROS, these antioxidants, which all creatures are extensibly endowed with. The consequences of oxygen activation in human bodies are only partly known, in spite of extensive scientific research on theoretical, experimental and clinical domains.

  16. Oxygen ion conducting materials

    DOEpatents

    Vaughey, John; Krumpelt, Michael; Wang, Xiaoping; Carter, J. David

    2003-01-01

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  17. Continuous home oxygen therapy.

    PubMed

    Ortega Ruiz, Francisco; Díaz Lobato, Salvador; Galdiz Iturri, Juan Bautista; García Rio, Francisco; Güell Rous, Rosa; Morante Velez, Fátima; Puente Maestu, Luis; Tàrrega Camarasa, Julia

    2014-05-01

    Oxygen therapy is defined as the therapeutic use of oxygen and consists of administering oxygen at higher concentrations than those found in room air, with the aim of treating or preventing hypoxia. This therapeutic intervention has been shown to increase survival in patients with chronic obstructive pulmonary disease (COPD) and respiratory failure. Although this concept has been extended by analogy to chronic respiratory failure caused by respiratory and non-respiratory diseases, continuous oxygen therapy has not been shown to be effective in other disorders. Oxygen therapy has not been shown to improve survival in patients with COPD and moderate hypoxaemia, nor is there consensus regarding its use during nocturnal desaturations in COPD or desaturations caused by effort. The choice of the oxygen source must be made on the basis of criteria such as technical issues, patient comfort and adaptability and cost. Flow must be adjusted to achieve appropriate transcutaneous oxyhaemoglobin saturation correction.

  18. Hyperbaric Oxygen Therapy Registry

    ClinicalTrials.gov

    2016-05-18

    Air or Gas Embolism; Carbon Monoxide Poisoning; Clostridial Myositis and Myonecrosis (Gas Gangrene); Crush Injury, Compartment Syndrome & Other Acute Traumatic Ischemias; Decompression Sickness; Peripheral Arterial Insufficiency and Central Retinal Artery Occlusion; Severe Anemia; Intracranial Abscess; Necrotizing Soft Tissue Infections; Osteomyelitis (Refractory); Delayed Radiation Injury (Soft Tissue and Bony Necrosis); Compromised Grafts and Flaps; Acute Thermal Burn Injury; Idiopathic Sudden Sensorineural Hearing Loss

  19. Ocean oxygen minima expansions and their biological impacts

    NASA Astrophysics Data System (ADS)

    Stramma, Lothar; Schmidtko, Sunke; Levin, Lisa A.; Johnson, Gregory C.

    2010-04-01

    Climate models with biogeochemical components predict declines in oceanic dissolved oxygen with global warming. In coastal regimes oxygen deficits represent acute ecosystem perturbations. Here, we estimate dissolved oxygen differences across the global tropical and subtropical oceans within the oxygen minimum zone (200-700-dbar depth) between 1960-1974 (an early period with reliable data) and 1990-2008 (a recent period capturing ocean response to planetary warming). In most regions of the tropical Pacific, Atlantic, and Indian Oceans the oxygen content in the 200-700-dbar layer has declined. Furthermore, at 200 dbar, the area with O 2 <70 μmol kg -1, where some large mobile macro-organisms are unable to abide, has increased by 4.5 million km 2. The tropical low oxygen zones have expanded horizontally and vertically. Subsurface oxygen has decreased adjacent to most continental shelves. However, oxygen has increased in some regions in the subtropical gyres at the depths analyzed. According to literature discussed below, fishing pressure is strong in the open ocean, which may make it difficult to isolate the impact of declining oxygen on fisheries. At shallower depths we predict habitat compression will occur for hypoxia-intolerant taxa, with eventual loss of biodiversity. Should past trends in observed oxygen differences continue into the future, shifts in animal distributions and changes in ecosystem structure could accelerate.

  20. Oxygen is an essential medicine: a call for international action

    PubMed Central

    Duke, T.; Graham, S. M.; Cherian, M. N.; Ginsburg, A. S.; English, M.; Howie, S.; Peel, D.; Enarson, P. M.; Wilson, I. H.; Were, W.

    2010-01-01

    SUMMARY Hypoxaemia is commonly associated with mortality in developing countries, yet feasible and cost-effective ways to address hypoxaemia receive little or no attention in current global health strategies. Oxygen treatment has been used in medicine for almost 100 years, but in developing countries most seriously ill newborns, children and adults do not have access to oxygen or the simple test that can detect hypoxaemia. Improving access to oxygen and pulse oximetry has demonstrated a reduction in mortality from childhood pneumonia by up to 35% in high-burden child pneumonia settings. The cost-effectiveness of an oxygen systems strategy compares favourably with other higher profile child survival interventions, such as new vaccines. In addition to its use in treating acute respiratory illness, oxygen treatment is required for the optimal management of many other conditions in adults and children, and is essential for safe surgery, anaesthesia and obstetric care. Oxygen concentrators provide the most consistent and least expensive source of oxygen in health facilities where power supplies are reliable. Oxygen concentrators are sustainable in developing country settings if a systematic approach involving nurses, doctors, technicians and administrators is adopted. Improving oxygen systems is an entry point for improving the quality of care. For these broad reasons, and for its vital importance in reducing deaths due to lung disease in 2010: Year of the Lung, oxygen deserves a higher priority on the global health agenda. PMID:20937173

  1. Atomic Oxygen Effects

    NASA Technical Reports Server (NTRS)

    Miller, Sharon K. R.

    2014-01-01

    Atomic oxygen, which is the most predominant species in low Earth orbit, is highly reactive and can break chemical bonds on the surface of a wide variety of materials leading to volatilization or surface oxidation which can result in failure of spacecraft materials and components. This presentation will give an overview of how atomic oxygen reacts with spacecraft materials, results of space exposure testing of a variety of materials, and examples of failures caused by atomic oxygen.

  2. Tropospheric Passive Remote Sensing

    NASA Technical Reports Server (NTRS)

    Keafer, L. S., Jr. (Editor)

    1982-01-01

    The long term role of airborne/spaceborne passive remote sensing systems for tropospheric air quality research and the identification of technology advances required to improve the performance of passive remote sensing systems were discussed.

  3. Elastomer Compatible With Oxygen

    NASA Technical Reports Server (NTRS)

    Martin, Jon W.

    1987-01-01

    Artificial rubber resists ignition on impact and seals at low temperatures. Filled fluoroelastomer called "Katiflex" developed for use in seals of vessels holding cold liquid and gaseous oxygen. New material more compatible with liquid oxygen than polytetrafluoroethylene. Provides dynamic seal at -196 degrees C with only 4 times seal stress required at room temperature. In contrast, conventional rubber seals burn or explode on impact in high-pressure oxygen, and turn hard or even brittle at liquid-oxygen temperatures, do not seal reliably, also see (MFS-28124).

  4. Solid state oxygen sensor

    DOEpatents

    Garzon, F.H.; Brosha, E.L.

    1997-12-09

    A potentiometric oxygen sensor is formed having a logarithmic response to a differential oxygen concentration while operating as a Nernstian-type sensor. Very thin films of mixed conducting oxide materials form electrode services while permitting diffusional oxygen access to the interface between the zirconia electrolyte and the electrode. Diffusion of oxygen through the mixed oxide is not rate-limiting. Metal electrodes are not used so that morphological changes in the electrode structure do not occur during extended operation at elevated temperatures. 6 figs.

  5. Monitoring Oxygen Status.

    PubMed

    Toffaletti, J G; Rackley, C R

    Although part of a common "blood gas" test panel with pH and pCO2, the pO2, %O2Hb, and related parameters are independently used to detect and monitor oxygen deficits from a variety of causes. Measurement of blood gases and cooximetry may be done by laboratory analyzers, point of care testing, noninvasive pulse oximetry, and transcutaneous blood gases. The specimen type and mode of monitoring oxygenation that are chosen may be based on a combination of urgency, practicality, clinical need, and therapeutic objectives. Because oxygen concentrations in blood are extremely labile, there are several highly important preanalytical practices necessary to prevent errors in oxygen and cooximetry results. Effective utilization of oxygen requires binding by hemoglobin in the lungs, transport in the blood, and release to tissues, where cellular respiration occurs. Hydrogen ion (pH), CO2, temperature, and 2,3-DPG all play important roles in these processes. Additional measurements and calculations are often used to interpret and locate the cause and source of an oxygen deficit. These include the Hb concentration, Alveolar-arterial pO2 gradient, pO2:FIO2 ratio, oxygenation index, O2 content and O2 delivery, and pulmonary dead space and intrapulmonary shunting. The causes of hypoxemia will be covered and, to illustrate how the oxygen parameters are used clinically in the diagnosis and management of patients with abnormal oxygenation, two clinical cases will be presented and described.

  6. Measuring tissue oxygenation

    NASA Technical Reports Server (NTRS)

    Soyemi, Olusola O. (Inventor); Soller, Babs R. (Inventor); Yang, Ye (Inventor)

    2009-01-01

    Methods and systems for calculating tissue oxygenation, e.g., oxygen saturation, in a target tissue are disclosed. In some embodiments, the methods include: (a) directing incident radiation to a target tissue and determining reflectance spectra of the target tissue by measuring intensities of reflected radiation from the target tissue at a plurality of radiation wavelengths; (b) correcting the measured intensities of the reflectance spectra to reduce contributions thereto from skin and fat layers through which the incident radiation propagates; (c) determining oxygen saturation in the target tissue based on the corrected reflectance spectra; and (d) outputting the determined value of oxygen saturation.

  7. Subsea downhole optical sensing

    NASA Astrophysics Data System (ADS)

    McStay, D.; Shiach, G.; McAvoy, S.

    2009-07-01

    The potential for subsea downhole optical fibre sensing to optimize hydrocarbon production and hence contribute to enhanced oil recovery is described. The components of susbea downhole optical sensing systems are reviewed and the performance of a new subsea optical fibre feed-through for downhole optical fibre sensing reported.

  8. The Impact of Vasoactive Drugs on Oxygenation and Tissue Perfusion

    DTIC Science & Technology

    1992-01-01

    useful in the management of congestive heart failure, cardiogenic pulmonary edema , mitral or aortic regurgitation and persistent chest pain...administration include refractory cardiac failure, cardiogenic shock, septic shock, post cardiac surgery, and acute renal failure (Opie, 1991; Budnv... cardiogenic , anaphylactic, and septic shock, and cardiac arrest (Zaritsky & Eisenberg, 1986). Affect on Oxygenation and Tissue Perfusion Epinephrine, as with

  9. Hazards of intubation in the ICU: role of nasal high flow oxygen therapy for preoxygenation and apneic oxygenation to prevent desaturation.

    PubMed

    Ricard, Jean D

    2016-10-01

    Acute respiratory failure is one the most common motives for intensive care unit admission. Although results from recent studies with high flow nasal oxygen have challenged our current management of these patients, a substantial number of them will require invasive mechanical ventilation and tracheal intubation. Life-threatening hypoxemia is the most frequent complication of these intubations. Desaturations occur despite properly conducted preoxygenation. Hence, alternatives are warranted to improve oxygenation during intubation. Two phases may be distinguished: the actual preoxygenation period (whilst the patient is still breathing spontaneously) and the laryngoscopy that requires rapid sequence induction. Noninvasive ventilation improves preoxygenation and limits desaturation but oxygen supply is interrupted to allow for laryngoscopy. High flow oxygen is increasingly used to manage patients with hypoxemic acute respiratory failure and can be maintained during the intubation procedure with the advantage of pursuing oxygen supply during patient's apnea, thereby providing apneic oxygenation. Discrepant results on the superiority of high flow oxygen compared to conventional facemask preoxygenation to limit desaturation during intubation highlight key determinants of effective apneic oxygenation: patent upper airway (importance of jaw thrust), and sufficient and constant administration of oxygen (high flows of 60 L/min rather than 15 L/min). Studies comparing high flow oxygen to noninvasive ventilation are ongoing and will help clarify the indications of each technique. This paper aims to show the evidence on the potential high flow nasal oxygen bears to improve preoxygenation for intubation outside the operating room. A practical algorithm to decide which preoxygenation device to use is proposed.

  10. Quantitating intracellular oxygen tension in vivo by phosphorescence lifetime measurement

    PubMed Central

    Hirakawa, Yosuke; Yoshihara, Toshitada; Kamiya, Mako; Mimura, Imari; Fujikura, Daichi; Masuda, Tsuyoshi; Kikuchi, Ryohei; Takahashi, Ippei; Urano, Yasuteru; Tobita, Seiji; Nangaku, Masaomi

    2015-01-01

    Hypoxia appears to have an important role in pathological conditions in many organs such as kidney; however, a method to quantify intracellular oxygen tension in vivo has not been well established. In this study, we established an optical method to quantify oxygen tension in mice kidneys using a cationic lipophilic phosphorescence probe, BTPDM1, which has an intracellular oxygen concentration-sensitive phosphorescence lifetime. Since this probe is distributed inside the tubular cells of the mice kidney, we succeeded in detecting acute renal hypoxic conditions and chronic kidney disease. This technique enabled us to estimate intracellular partial pressures of oxygen in vivo by extrapolating the calibration curve generated from cultured tubular cells. Since intracellular oxygen tension is directly related to cellular hypoxic reactions, such as the activation of hypoxia-inducible factors, our method will shed new light on hypoxia research in vivo. PMID:26644023

  11. Oxygen sensitive paper

    NASA Technical Reports Server (NTRS)

    Whidby, J. F.

    1973-01-01

    Paper is impregnated with mixture of methylene blue and ethylenediaminetetraacetic acid. Methylene blue is photo-reduced to leuco-form. Paper is kept isolated from oxygen until ready for use. Paper can be reused by photo-reduction after oxygen exposure.

  12. Durability of oxygen sensors

    NASA Astrophysics Data System (ADS)

    Snapp, L.

    1985-03-01

    This report describes the results of dynamometer and vehicle durability testing from a variety of sources, as well as common causes of failure for oxygen sensors. The data indicates that oxygen sensors show low failure rates, even at mileages of 80,000 miles and beyond.

  13. Blood Oxygenation Level-Dependent MRI to Assess Renal Oxygenation in Renal Diseases: Progresses and Challenges

    PubMed Central

    Pruijm, Menno; Milani, Bastien; Burnier, Michel

    2017-01-01

    BOLD-MRI (blood oxygenation-level dependent magnetic resonance imaging) allows non-invasive measurement of renal tissue oxygenation in humans, without the need for contrast products. BOLD-MRI uses the fact that magnetic properties of hemoglobin depend of its oxygenated state:: the higher local deoxyhemoglobin, the higher the so called apparent relaxation rate R2* (sec−1), and the lower local tissue oxygen content. Several factors other than deoxyhemoglobin (such as hydration status, dietary sodium intake, and susceptibility effects) influence the BOLD signal, and need to be taken into account when interpreting results. The last 5 years have witnessed important improvements in the standardization of these factors, and the appearance of new, highly reproducible analysis techniques of BOLD-images, that are reviewed in this article. Using these new BOLD-MRI analysis techniques, it has recently been shown that persons suffering from chronic kidney diseases (CKD) have lower cortical oxygenation than normotensive controls, thus confirming the chronic hypoxia hypothesis. The acute alterations in R2* after the administration of furosemide are smaller in CKD, and represent an estimate of the oxygen-dependent tubular transport of sodium. BOLD-MRI-alone or in combination with other functional MRI methods- can be used to monitor the renal effects of drugs, and is increasingly used in the preclinical setting. The near future will tell whether or not BOLD-MRI represents a new tool to predict renal function decline an adverse renal outcome. PMID:28105019

  14. Atomic Oxygen Textured Polymers

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Hunt, Jason D.; Drobotij, Erin; Cales, Michael R.; Cantrell, Gidget

    1995-01-01

    Atomic oxygen can be used to microscopically alter the surface morphology of polymeric materials in space or in ground laboratory facilities. For polymeric materials whose sole oxidation products are volatile species, directed atomic oxygen reactions produce surfaces of microscopic cones. However, isotropic atomic oxygen exposure results in polymer surfaces covered with lower aspect ratio sharp-edged craters. Isotropic atomic oxygen plasma exposure of polymers typically causes a significant decrease in water contact angle as well as altered coefficient of static friction. Such surface alterations may be of benefit for industrial and biomedical applications. The results of atomic oxygen plasma exposure of thirty-three (33) different polymers are presented, including typical morphology changes, effects on water contact angle, and coefficient of static friction.

  15. Plant gravity sensing

    NASA Technical Reports Server (NTRS)

    Sack, F. D.

    1991-01-01

    This review of plant gravity sensing examines sensing in organ gravitropism, sensing in single-cell gravitropism, and nongravitropic sensing. Topics related to sensing in organ gravitropism are (1) identification of the gravitropic susceptors, including intracellular asymmetry in equilibrium position and after reorientation, susceptor signal-to-noise ratio, signal integration over threshold stimulation periods, intracellular asymmetry and gravitropic competence, and starch deficiency and gravitropic competence; (2) possible root statocytes and receptors, including identification of presumptive statocytes, cytology, and possible receptors and models of sensing; and (3) negatively gravitropic organs, including identification and distribution of presumptive statocytes and cytology and possible receptors. Topics related to nongravitropic sensing include gravitaxis, reaction wood, gravimorphogenesis, other gravity-influenced organ movements, and cytoplasmic streaming.

  16. Plant gravity sensing.

    PubMed

    Sack, F D

    1991-01-01

    This review of plant gravity sensing examines sensing in organ gravitropism, sensing in single-cell gravitropism, and nongravitropic sensing. Topics related to sensing in organ gravitropism are (1) identification of the gravitropic susceptors, including intracellular asymmetry in equilibrium position and after reorientation, susceptor signal-to-noise ratio, signal integration over threshold stimulation periods, intracellular asymmetry and gravitropic competence, and starch deficiency and gravitropic competence; (2) possible root statocytes and receptors, including identification of presumptive statocytes, cytology, and possible receptors and models of sensing; and (3) negatively gravitropic organs, including identification and distribution of presumptive statocytes and cytology and possible receptors. Topics related to nongravitropic sensing include gravitaxis, reaction wood, gravimorphogenesis, other gravity-influenced organ movements, and cytoplasmic streaming.

  17. Sense and clinical sensibility.

    PubMed

    Billow, Richard M

    2013-10-01

    I call attention to the metapsychology of sense, and the role sense plays-phenomenologically and symbolically-in the life of the clinician and the group. Each group member asserts influence in taking a role as the perceiver and the perceived, the senser and the sensed. We reach for sense, for without sense reference, we cannot grasp or even talk about psychic reality. It serves as sign and symbol, as metaphor, analogy, illustration, and model. Sense fixes experience yet may fixate experience and interfere with developing abstract thoughts. Clinical vignettes illustrate how the leader may utilize his or her particular clinical sensibility to reach the group and focus attention, to link sense to psychic qualities: to the personality of the members, the group culture and process, and the live clinical interaction.

  18. Pressure broadening of oxygen by water

    NASA Astrophysics Data System (ADS)

    Drouin, Brian J.; Payne, Vivienne; Oyafuso, Fabiano; Sung, Keeyoon; Mlawer, Eli

    2014-01-01

    A need for precise air-mass retrievals utilizing the near-infrared O2 A-band has motivated measurements of the water-broadening in oxygen. Experimental challenges have resulted in very little water broadened oxygen data. Existing water broadening data for the O2 A-band is of insufficient precision for application to the atmospheric data. Line shape theory suggests that approximate O2 pressure broadening parameters for one spectral region, such as the A-band, may be obtained from comparable spectral regions such as the O2 60 GHz Q-branch, which is also used prominently in remote sensing. We have measured precise O2-H2O broadening for the 60 GHz Q-branch and the pure-rotational transitions at room temperature with a Zeeman-modulated absorption cell using a frequency-multiplier spectrometer. Intercomparisons of these data and other O2 pressure broadening data sets confirm the expectation of only minor band-to-band scaling of pressure broadening. The measurement provides a basis for fundamental parameterization of retrieval codes for the long-wavelength atmospheric measured values. Finally, we demonstrate the use of these measurements for retrievals of air-mass via remote sensing of the oxygen A-band.

  19. The sense of consciousness.

    PubMed

    Tannenbaum, A S

    2001-08-21

    I propose that consciousness might be understood as the property of a system that functions as a sense in the biological meaning of that term. The theory assumes that, as a complex system, the sense of consciousness is not a fixed structure but implies structure with variations and that it evolved, as many new functions do, through the integration of simpler systems. The recognized exteroceptive and enteroceptive senses provide information about the organism's environment and about the organism itself that are important to adaptation. The sense of consciousness provides information about the brain and thus about the organism and its environment. It senses other senses and processes in the brain, selecting and relating components into a form that "makes sense"-where making sense is defined as being useful to the organism in its adaptation to the environment. The theory argues that this highly adaptive organizing function evolved with the growing complexity of the brain and that it might have helped resolve discrepancies created at earlier stages. Neural energies in the brain that are the input to the sense of consciousness, along with the processing subsystem of which they are a part, constitute the base of consciousness. Consciousness itself is an emergent effect of an organizing process achieved through the sense of consciousness. The sense of consciousness thus serves an organizing function although it is not the only means of organization in the brain. Its uniqueness lies in the character of the organization it creates with consciousness as a property of that organization. The paper relates the theory to several general conceptions-interactionism, epiphenomenalism and identity theory-and illustrates a number of testable hypotheses. Viewing consciousness as a property of a sense provides a degree of conceptual integration. Much of what we know about the evolution and role of the conventionally recognized senses should help us understand the evolution and role of

  20. Photoacoustic lifetime imaging for direct in vivo tissue oxygen monitoring

    NASA Astrophysics Data System (ADS)

    Shao, Qi; Ashkenazi, Shai

    2015-03-01

    Measuring the partial pressure of oxygen (pO2) in tissue may provide physicians with essential information about the physiological state of tissue. However, currently available methods for measuring or imaging tissue pO2 have significant limitations, preventing them from being widely used in clinics. Recently, we have reported a direct and noninvasive in vivo imaging modality based on the photoacoustic lifetime which overcomes certain drawbacks of the existing methods. The technique maps the excited triplet state of oxygen-sensitive dye, thus reflecting the spatial and temporal distributions of tissue oxygen. Here, we present two studies which apply photoacoustic lifetime imaging (PALI) to monitor changes of tissue oxygen induced by external modulations. The first study modulates tissue oxygen by controlling the percentage of oxygen a normal mouse inhales. We demonstrate that PALI is able to reflect the change in oxygen level with respect to normal, oxygen-rich, and oxygen-poor breathing conditions. The second study involves an acute ischemia model using a thin thread tied around the hindlimb of a normal mouse to reduce the blood flow. PALI images were acquired before, during, and after the restriction. The drop of tissue pO2 and recovery from hypoxia due to reperfusion were tracked and observed by PALI.

  1. Atomic Oxygen Fluence Monitor

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.

    2011-01-01

    This innovation enables a means for actively measuring atomic oxygen fluence (accumulated atoms of atomic oxygen per area) that has impinged upon spacecraft surfaces. Telemetered data from the device provides spacecraft designers, researchers, and mission managers with real-time measurement of atomic oxygen fluence, which is useful for prediction of the durability of spacecraft materials and components. The innovation is a compact fluence measuring device that allows in-space measurement and transmittance of measured atomic oxygen fluence as a function of time based on atomic oxygen erosion yields (the erosion yield of a material is the volume of material that is oxidized per incident oxygen atom) of materials that have been measured in low Earth orbit. It has a linear electrical response to atomic oxygen fluence, and is capable of measuring high atomic oxygen fluences (up to >10(exp 22) atoms/sq cm), which are representative of multi-year low-Earth orbital missions (such as the International Space Station). The durability or remaining structural lifetime of solar arrays that consist of polymer blankets on which the solar cells are attached can be predicted if one knows the atomic oxygen fluence that the solar array blanket has been exposed to. In addition, numerous organizations that launch space experiments into low-Earth orbit want to know the accumulated atomic oxygen fluence that their materials or components have been exposed to. The device is based on the erosion yield of pyrolytic graphite. It uses two 12deg inclined wedges of graphite that are over a grit-blasted fused silica window covering a photodiode. As the wedges erode, a greater area of solar illumination reaches the photodiode. A reference photodiode is also used that receives unobstructed solar illumination and is oriented in the same direction as the pyrolytic graphite covered photodiode. The short-circuit current from the photodiodes is measured and either sent to an onboard data logger, or

  2. Acute laminitis.

    PubMed

    Baxter, G M

    1994-12-01

    Laminitis is an inflammation of the sensitive laminae along the dorsal aspect of the digit and is considered to be a secondary complication of several predisposing or primary factors. Affected horses are usually very lame, have increased digital pulses, are painful to hoof testers along the toe of the foot, and have evidence of downward rotation or distal displacement of the distal phalanx present on radiographs. Treatments for acute laminitis include anti-inflammatory drugs, anti-endotoxin therapy, vasodilators, antithrombotic therapy, corrective trimming and shoeing, and surgical procedures. Treatment regimens are very controversial and the true efficacy of these treatments is unknown. The quality of laminae damage that occurs with laminitis, however, probably has greater influence on the success of treatment and outcome of the horse than the treatment regimen itself.

  3. Synthetic carriers of oxygen.

    PubMed

    Dellacherie, E; Labrude, P; Vigneron, C; Riess, J G

    1987-01-01

    During the last decade, construction of artificial carriers of oxygen for transfusion purposes has evolved in three main directions, which can be reviewed as follows. The first approach consists of modifying hemoglobin (Hb), the natural oxygen carrier, in order to lower its oxygen affinity and increase its intravascular persistence. To achieve this aim, two basic procedures have been used: molecular and environmental modification. In the first case, Hb is modified with chemical reagents; the second requires encapsulation of Hb to obtain artificial erythrocytes. The second approach is based on the use of synthetic oxygen-carrying chelates that mimic the oxygenation function of Hb. The main products in this class are metalloporphyrins, whose chemical environment is designed to render them efficient as reversible carriers of oxygen in vivo. Finally, the third approach deals with the perfluorochemicals used in emulsified form. Perfluorochemical liquids are excellent gas solvents, but some problems remain unsolved with regard to their development as oxygen carriers in vivo: low O2 dissolving capacity, toxicity, and excretion.

  4. Electrochemical oxygen concentrator as an oxygen compressor

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A solid polymer electrolyte (SPE) oxygen compressor is described which generates pressures of 3000 psi. The SPE is a cation exchange membrane with chemical compatibility, and has the capability of withstanding 5000 psi. Other features of the compressor described include: gasketless sealing, porus plate cell supports, and conductive cooling. Results are presented of a computer program which defines the power of the system as a function of density, temperature, pressure, membrane thickness, and water content.

  5. Optical methods and systems for detecting a constituent in a gas containing oxygen in harsh environments

    SciTech Connect

    Carpenter, Michael A.; Sirinakis, George

    2011-01-04

    A method for detecting a gas phase constituent such as carbon monoxide, nitrogen dioxide, hydrogen, or hydrocarbons in a gas comprising oxygen such as air, includes providing a sensing material or film having a metal embedded in a catalytically active matrix such as gold embedded in a yttria stabilized zirconia (YSZ) matrix. The method may include annealing the sensing material at about 900.degree. C., exposing the sensing material and gas to a temperature above 400.degree. C., projecting light onto the sensing material, and detecting a change in the absorption spectrum of the sensing material due to the exposure of the sensing material to the gas in air at the temperature which causes a chemical reaction in the sensing material compared to the absorption spectrum of the sensing material in the absence of the gas. Systems employing such a method are also disclosed.

  6. Oxygen cycling in the northern Benguela Upwelling System: Modelling oxygen sources and sinks

    NASA Astrophysics Data System (ADS)

    Schmidt, Martin; Eggert, Anja

    2016-12-01

    This paper elucidates the oxygen dynamics in the northern Benguela Upwelling System by means of process oriented, numerical modelling. Owing to the complex physical-biological interaction in this system, a coupled hydrodynamic-biogeochemical model is required to grasp the various aspects of the oxygen dynamics. We used high-resolution atmospheric fields derived from observations to force our model, available since 1999. The model results represent a 15 years, consistent data set of realistic hydrographic and ecosystem variables, including oxygen distribution patterns. After a concise description of the main aspects of the model, we use the model data to analyse the components contributing to the oxygen dynamics, namely, the ocean circulation, the exchange between ocean and atmosphere as well as the local biogeochemical oxygen cycling in the system. We thoroughly validate the model with available field observations and remote sensing data. The strengths of coastal upwelling, which controls the nutrient supply to the euphotic zone, as well as the poleward undercurrent that carries oxygen and nutrients to the shelf in the northern Benguela Upwelling System are well reproduced in the model. Among the biological oxygen sinks, mineralisation in the sediment, respiration of zooplankton and nitrification in the water column are important. We also found that vertical migration of zooplankton in response to the oxygen conditions provides a regulating feedback, which may prevent a complete deoxygenation of suboxic waters. As long as oxygen or nitrate are available in the bottom waters, the activities of chemolithoautotrophic sulphur bacteria on the sediment surface keep the redoxcline within the sediment and prevent the release of hydrogen sulphide into the water column. By horizontal integration of the simulated ocean-atmosphere oxygen flux, it can be shown that the Kunene upwelling cell between 16 ° S and 18 ° S is a boundary between the equatorial ocean, characterise by

  7. REMOTE SENSING IN OCEANOGRAPHY.

    DTIC Science & Technology

    remote sensing from satellites. Sensing of oceanographic variables from aircraft began with the photographing of waves and ice. Since then remote measurement of sea surface temperatures and wave heights have become routine. Sensors tested for oceanographic applications include multi-band color cameras, radar scatterometers, infrared spectrometers and scanners, passive microwave radiometers, and radar imagers. Remote sensing has found its greatest application in providing rapid coverage of large oceanographic areas for synoptic and analysis and

  8. Learning Circulant Sensing Kernels

    DTIC Science & Technology

    2012-08-01

    Nowak. Toeplitz compressed sensing matrices with applications to sparse channel estimation . Submitted to IEEE Transactions on Information Theory , 2008...11] J. Haupt, W.U. Bajwa, G. Raz, and R. Nowak. Toeplitz compressed sensing matrices with applications to sparse channel estimation . Information...Y. Li, N. Nguyen, W. Yin, and Z. Han. High resolution OFDM channel estimation with low speed ADC using compressive sensing . IEEE ICC 2011 Signal

  9. Learning Circulant Sensing Kernels

    DTIC Science & Technology

    2014-03-01

    Compressive sensing based high resolution channel estimation for OFDM system. To appear in IEEE Journal of Selected Topics in Signal Processing, Special...and R. D. Nowak. Toeplitz compressed sensing ma- trices with applications to sparse channel estimation . Submitted to IEEE Transactions on Information...various applications. For compressive sens- ing, recent work has used random Toeplitz and circulant sensing matrices and proved their efficiency in theory

  10. Oxygen and Biological Evolution.

    ERIC Educational Resources Information Center

    Baugh, Mark A.

    1990-01-01

    Discussed is the evolution of aerobic organisms from anaerobic organisms and the accompanying biochemistry that developed to motivate and enable this evolution. Uses of oxygen by aerobic organisms are described. (CW)

  11. Hyperbaric Oxygen Therapy

    MedlinePlus

    ... causes tissue death Nonhealing wounds, such as a diabetic foot ulcer Radiation injury Skin graft or skin flap ... hyperbaric oxygenation therapy in the management of chronic diabetic foot ulcers. Mayo Clinic Proceedings. 2013;88:166. Indications ...

  12. OXYGEN TRANSPORT CERAMIC MEMBRANES

    SciTech Connect

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2002-07-01

    In the present quarter, oxygen transport perovskite ceramic membranes are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

  13. Medical Oxygen Safety

    MedlinePlus

    ... injuries and deaths. from a heat source, open flames or electrical devices. KKK Body oil, hand lotion ... the oxygen. Post No Smoking and No Open Flames signs in and outside the home to remind ...

  14. High Selectivity Oxygen Delignification

    SciTech Connect

    Lucian A. Lucia

    2005-11-15

    Project Objective: The objectives of this project are as follows: (1) Examine the physical and chemical characteristics of a partner mill pre- and post-oxygen delignified pulp and compare them to lab generated oxygen delignified pulps; (2) Apply the chemical selectivity enhancement system to the partner pre-oxygen delignified pulps under mill conditions (with and without any predetermined amounts of carryover) to determine how efficiently viscosity is preserved, how well selectivity is enhanced, if strength is improved, measure any yield differences and/or bleachability differences; and (3) Initiate a mill scale oxygen delignification run using the selectivity enhancement agent, collect the mill data, analyze it, and propose any future plans for implementation.

  15. A novel microbial fuel cell sensor with biocathode sensing element.

    PubMed

    Jiang, Yong; Liang, Peng; Liu, Panpan; Wang, Donglin; Miao, Bo; Huang, Xia

    2017-03-02

    The traditional microbial fuel cell (MFC) sensor with bioanode as sensing element delivers limited sensitivity to toxicity monitoring, restricted application to only anaerobic and organic rich water body, and increased potential fault warning to the combined shock of organic matter/toxicity. In this study, the biocathode for oxygen reduction reaction was employed for the first time as the sensing element in MFC sensor for toxicity monitoring. The results shown that the sensitivity of MFC sensor with biocathode sensing element (7.4±2.0 to 67.5±4.0mA%(-1)cm(-2)) was much greater than that showed by bioanode sensing element (3.4±1.5 to 5.5±0.7mA%(-1)cm(-2)). The biocathode sensing element achieved the lowest detection limit reported to date using MFC sensor for formaldehyde detection (0.0005%), while the bioanode was more applicable for higher concentration (>0.0025%). There was a quicker response of biocathode sensing element with the increase of conductivity and dissolved oxygen (DO). The biocathode sensing element made the MFC sensor directly applied to clean water body monitoring, e.g., drinking water and reclaimed water, without the amending of background organic matter, and it also decreased the warning failure when challenged by a combined shock of organic matter/toxicity.

  16. Short-burst oxygen therapy for COPD patients: a 6-month randomised, controlled study.

    PubMed

    Eaton, T; Fergusson, W; Kolbe, J; Lewis, C A; West, T

    2006-04-01

    Short-burst oxygen therapy (SBOT) remains widely advocated for patients with chronic obstructive pulmonary disease (COPD), despite a lack of supporting evidence. The aim of this randomised, double-blind, placebo-controlled, parallel group study was to determine whether SBOT improves health-related quality of life (HRQL) or reduces acute healthcare utilisation in patients discharged following an acute exacerbation of COPD. Consecutive patients were screened; 78 of 331 were eligible for randomisation to cylinder oxygen, cylinder air or usual care following discharge. Patients were elderly with high acute healthcare utilisation, forced expiratory volume in one second of <1 L and had dyspnoea limiting daily activity but were not hypoxaemic at rest. Over the 6-month study period, there were no significant differences between patient groups in HRQL (Chronic Respiratory Questionnaire (CRQ), 36-item Short-Form Health Survey, Hospital Anxiety and Depression Scale) except for CRQ emotion domain. There were no significant differences in acute healthcare utilisation. Time to readmission was greatest in the usual care group. Cylinder use was high initially, but rapidly fell to very low levels within weeks in both cylinder oxygen and air groups. In conclusion, the availability of short-burst oxygen therapy for chronic obstructive pulmonary disease patients discharged from hospital following an acute exacerbation did not improve health-related quality of life or reduce acute healthcare utilisation. These results provide no support for the widespread use of short-burst oxygen therapy.

  17. Advanced Remote Sensing Research

    USGS Publications Warehouse

    Slonecker, Terrence; Jones, John W.; Price, Susan D.; Hogan, Dianna

    2008-01-01

    'Remote sensing' is a generic term for monitoring techniques that collect information without being in physical contact with the object of study. Overhead imagery from aircraft and satellite sensors provides the most common form of remotely sensed data and records the interaction of electromagnetic energy (usually visible light) with matter, such as the Earth's surface. Remotely sensed data are fundamental to geographic science. The Eastern Geographic Science Center (EGSC) of the U.S. Geological Survey (USGS) is currently conducting and promoting the research and development of three different aspects of remote sensing science: spectral analysis, automated orthorectification of historical imagery, and long wave infrared (LWIR) polarimetric imagery (PI).

  18. Dissolved oxygen: Chapter 6

    USGS Publications Warehouse

    Senn, David; Downing-Kunz, Maureen; Novick, Emily

    2016-01-01

    Dissolved oxygen (DO) concentration serves as an important indicator of estuarine habitat condition, because all aquatic macro-organisms require some minimum DO level to survive and prosper. The instantaneous DO concentration, measured at a specific location in the water column, results from a balance between multiple processes that add or remove oxygen (Figure 6.1): primary production produces O2; aerobic respiration in the water column and sediments consumes O2; abiotic or microbially-mediated biogeochemical reactions utilize O2 as an oxidant (e.g., oxidation of ammonium, sulfide, and ferrous iron); O2 exchange occurs across the air:water interface in response to under- or oversaturated DO concentrations in the water column; and water currents and turbulent mixing transport DO into and out of zones in the water column. If the oxygen loss rate exceeds the oxygen production or input rate, DO concentration decreases. When DO losses exceed production or input over a prolonged enough period of time, hypoxia ((<2-3 mg/L) or anoxia can develop. Persistent hypoxia or anoxia causes stress or death in aquatic organism populations, or for organisms that can escape a hypoxic or anoxic area, the loss of habitat. In addition, sulfide, which is toxic to aquatic organisms and causes odor problems, escapes from sediments under low oxygen conditions. Low dissolved oxygen is a common aquatic ecosystem response to elevated organic

  19. [Oxygen Leukocyte Larceny].

    PubMed

    Pinto da Costa, Miguel; Pimenta Coelho, Henrique

    2016-05-01

    The authors present a case of a 60-year-old male patient, previously diagnosed with B-cell chronic lymphocytic leukemia, who was admitted to the Emergency Room with dyspnea. The initial evaluation revealed severe anemia (Hgb = 5.0 g/dL) with hyperleukocytosis (800.000/µL), nearly all of the cells being mature lymphocytes, a normal chest X-ray and a low arterial oxygen saturation (89%; pulse oximetry). After red blood cell transfusion, Hgb values rose (9.0 g/dL) and there was a complete reversion of the dyspnea. Yet, subsequent arterial blood gas analysis, without the administration of supplemental oxygen, systematically revealed very low oxygen saturation values (~ 46%), which was inconsistent with the patientâs clinical state and his pulse oximetry values (~ 87%), and these values were not corrected by the administration of oxygen via non-rebreather mask. The investigation performed allowed to establish the diagnosis of oxygen leukocyte larceny, a phenomenon which conceals the true oxygen saturation due to peripheral consumption by leukocytes.

  20. Ultra-sensitive optical oxygen sensors for characterisation of nearly anoxic systems

    PubMed Central

    Lehner, Philipp; Staudinger, Christoph; Borisov, Sergey M.; Klimant, Ingo

    2014-01-01

    Oxygen quantification in trace amounts is essential in many fields of science and technology. Optical oxygen sensors proved invaluable tools for oxygen measurements in a broad concentration range but until now neither optical nor electrochemical oxygen sensors were able to quantify oxygen in the sub-nanomolar concentration range. Herein we present new optical oxygen sensing materials with unmatched sensitivity. They rely on the combination of ultra-long decaying (several hundred milliseconds lifetime) phosphorescent boron- and aluminium-chelates and highly oxygen-permeable and chemically stable perfluorinated polymers. The sensitivity of the new sensors is improved up to 20-fold compared to state-of-the-art analogues. The limits of detection are as low as 5 parts per billion, volume in gas phase under atmospheric pressure or 7 picomolar in solution. The sensors enable completely new applications for monitoring of oxygen in previously inaccessible concentration ranges. PMID:25042041

  1. Acute asthma: under attack.

    PubMed

    Kissoon, Niranjan

    2002-06-01

    The burden of asthma (death, disability, and an increasing prevalence) makes it a major public health problem worldwide. In an effort to decrease this burden, investigators are studying many aspects of this disease. The role of race, ethnicity, infections, and pollutants as triggers, as well as the risk factors are now being defined. Research into methods to decrease acute exacerbations and improve emergency and in-hospital management, using standardized protocols and incentives for follow-up care, has yielded valuable information but has met with limited success. Adherence to the national guidelines has been poor and to some extent can be attributed to the lack of a practical method of measuring the degree of lung inflammation and cumbersome treatment protocols. Exhaled nitric oxide is a noninvasive marker of inflammation and may provide a rational method to titrate corticosteroid and leukotriene receptor antagonist therapy. The best route and dosing regimen for corticosteroid administration (oral vs intramuscular vs nebulized) are the subject of several studies, with no clear-cut winner. The burden of asthma in developing countries with limited financial resources has also triggered a search for simpler, cheaper, and practical methods for beta-agonist delivery using indigenous spacers. Recent research in asthma has unveiled our incomplete knowledge of the disease but has also provided a sense of where efforts should be expended. Research into the genetics and pharmacogenetics of asthma and into the societal factors limiting the delivery of optimal care is likely to yield useful and practical information.

  2. [Problems in maintenance therapy in acute myeloid leukemias in adults].

    PubMed

    Gürtler, R; Raderecht, C

    1975-01-01

    Problems of maintaining therapy for acute myelocytic leukemias in adults are discussed. The analysis of the maintaining therapy in 22 patients affected with an acute myelocytic leukemia and living for more than 6 months revealed that the interval therapy with a high dosage of cytostatic combinations in the sense of the COAP scheme is preferable compared with the daily administration of 6-mercaptopurin, in addition methotrexate twice a week. Reasons for this are discussed.

  3. Longevity, oxygen toxicity and radiation-enhanced resistance to oxygen in tribolium confusum

    SciTech Connect

    Lee, Y.J.

    1985-01-01

    Sublethal doses of ionizing radiation increase longevity in a variety of insects suggesting that irradiation may retard the age-dependent decline of physiological functions. There have been no systematic investigations of the response of irradiated populations to stress, however. The authors have demonstrated that resistance of adult flour beetles, Tribolium confusum, to oxygen poisoning declines progressively with age. They have examined oxygen resistance of irradiated populations of T. confusum as a function of age at irradiation, of time after irradiation, and of radiation dose and of dose-modifying factors. Shortly after gamma-irradiation, flour beetles exhibited a decline in resistance to oxygen toxicity. Then, about two weeks after irradiation, the LD/sub 50/ exposure time in pure oxygen was much greater than that of nonirradiated beetles, and this enhanced resistance persisted for about 6 months. The magnitude of the enhancement was a function of dose, decreased with increasing age at irradiation, and was modified by radiation factors. Sublethal irradiation under anoxia, at low dose rate, or with dose fractionation reduced the development of oxygen resistance to approximately the same degree that it reduced acute radiation lethality . Radiation-enhanced resistance to stress may be an important factor in the increased longevity of irradiated insects.

  4. [High flow, humidified-reheated oxygen therapy: a new oxygenation technique for adults].

    PubMed

    Frat, J-P; Goudet, V; Girault, C

    2013-10-01

    Currently conventional oxygen therapy is the first choice symptomatic treatment in the management of acute respiratory failure (ARF). However, conventional oxygen therapy has important limitations which have lead to the development of heated and humidified high-flow nasal oxygen therapy (HFNO). HFNO is an innovative technique that can deliver, through special nasal cannulae, up to 100% of the inspired fraction (FiO2) with heated and humidified oxygen at a maximum flow of 70L/min. The characteristics of this technique (overcoming the patient's spontaneous inspiratory flow, heated humidification,) and its physiological effects (no dilution of FiO2, positive end-expiratory pressure, pharyngeal dead-space washout, decrease in airway resistance), allow efficient optimization of oxygenation with better tolerance for patients. Current data, mainly observational, show that HFNO could be used particularly for the management of hypoxemic ARF, notably in the more severe forms. Indications for using HFNO, alone or in association with noninvasive ventilation, are potentially very broad and may involve different types of ARF (post-operative, post-extubation, palliative care) and even the practice of invasive technical procedures (bronchial fibroscopy). However, though current studies are very encouraging and promise a clinical benefit on patient outcomes, randomized trials are still needed to demonstrate that HFNO avoids the need for endotracheal intubation in the management of ARF.

  5. Into Thin Air: How We Sense and Respond to Hypoxia.

    PubMed

    Thompson, Craig B

    2016-09-22

    This year's Lasker Basic Medical Research Award is shared by William Kaelin, Peter Ratcliffe, and Gregg Semenza for discovery of the pathway by which animal cells sense and adapt to changes in oxygen availability, which plays an essential role in adaptation to a wide variety of physiologic and pathologic conditions.

  6. Neonatal Acute Kidney Injury.

    PubMed

    Selewski, David T; Charlton, Jennifer R; Jetton, Jennifer G; Guillet, Ronnie; Mhanna, Maroun J; Askenazi, David J; Kent, Alison L

    2015-08-01

    In recent years, there have been significant advancements in our understanding of acute kidney injury (AKI) and its impact on outcomes across medicine. Research based on single-center cohorts suggests that neonatal AKI is very common and associated with poor outcomes. In this state-of-the-art review on neonatal AKI, we highlight the unique aspects of neonatal renal physiology, definition, risk factors, epidemiology, outcomes, evaluation, and management of AKI in neonates. The changes in renal function with gestational and chronologic age are described. We put forth and describe the neonatal modified Kidney Diseases: Improving Global Outcomes AKI criteria and provide the rationale for its use as the standardized definition of neonatal AKI. We discuss risk factors for neonatal AKI and suggest which patient populations may warrant closer surveillance, including neonates <1500 g, infants who experience perinatal asphyxia, near term/ term infants with low Apgar scores, those treated with extracorporeal membrane oxygenation, and those requiring cardiac surgery. We provide recommendations for the evaluation and treatment of these patients, including medications and renal replacement therapies. We discuss the need for long-term follow-up of neonates with AKI to identify those children who will go on to develop chronic kidney disease. This review highlights the deficits in our understanding of neonatal AKI that require further investigation. In an effort to begin to address these needs, the Neonatal Kidney Collaborative was formed in 2014 with the goal of better understanding neonatal AKI, beginning to answer critical questions, and improving outcomes in these vulnerable populations.

  7. Gravi-sensing microorganisms as model systems for gravity sensing in eukaryotes

    NASA Astrophysics Data System (ADS)

    Streb, C.; Richter, P.; Lebert, M.; Häder, D.-P.

    2001-08-01

    Gravi-sensing in single cells and multicellular organisms is a very active field of investigation. Similarities between gravity sensing mechanisms in uni- and multicellular eukaryotes make single cells ideal model systems for the understanding of gravity responses on the cellular and molecular level with far fetching significance for other systems. This article gives a short overview about gravi-sensing in plants (Arabidopsis, Chara) as well as the ciliates Loxodes and Paramecium and concentrates on gravitaxis research in the single cellular flagellate, Euglena gracilis. Experiments revealed the involvement of cAMP, Ca2+ specific mechanosensitive channels and membrane potential in the signal transduction chain of gravitaxis. Future perspectives for the use of motile, photosynthetic and other unicellular microorganisms for space applications e.g. for oxygen supply in life support systems or research on the origin of life are discussed.

  8. Sound and Sense.

    ERIC Educational Resources Information Center

    Fleischman, Paul

    1986-01-01

    Claims that in metrical prose, rhythm can convey sense or express and underline what a writer is saying, and sound can be exploited to add a strong aural element that provides pleasure to the ears over and above the pleasure given by the sense of story. (SRT)

  9. Remote sensing applications program

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The activities of the Mississippi Remote Sensing Center are described in addition to technology transfer and information dissemination, remote sensing topics such as timber identification, water quality, flood prevention, land use, erosion control, animal habitats, and environmental impact studies are also discussed.

  10. Making Sense: Kinesthesia.

    ERIC Educational Resources Information Center

    Zion, Leela C.

    1996-01-01

    Discusses the senses as being more than just the usual five senses, but sensory systems. Explains technical details of the operation of each system. Defines kinesthesia as a sensory system also, and its responsibility for movement and instinctive knowledge of movement in space/time. Relates how children learn kinesthetically by using examples such…

  11. Promote Number Sense

    ERIC Educational Resources Information Center

    Gurganus, Susan

    2004-01-01

    "Number sense" is "an intuition about numbers that is drawn from all varied meanings of number" (NCTM, 1989, p. 39). Students with number sense understand that numbers are representative of objects, magnitudes, relationships, and other attributes; that numbers can be operated on, compared, and used for communication. It is fundamental knowledge…

  12. Sensing Surveillance & Navigation

    DTIC Science & Technology

    2012-03-07

    Fully Adaptive Radar” Sensor Processing including MIMO Sensing for Object Identification: Analysis and Synthesis of Invariants Integrated...Operators are overwhelmed by massive volumes of high dimensional multi-sensor data • Challenges -Efficiently process data to extract inherent...Sensing & Surveillance Systems • Develop toolkit for matrix treatment of MIMO radar wave-forms • Multiple-Input/Multiple-Output • enable performance

  13. Math Sense: Comprehensive Review.

    ERIC Educational Resources Information Center

    Hoyt, Cathy Fillmore

    This book features a comprehensive review of the Math Sense series and is designed to help students gain the range of math skills they need to succeed in life, work, and on standardized tests; overcome math anxiety; discover math as interesting and purposeful; and develop good number sense. Topics covered in this book include whole numbers;…

  14. Land Remote Sensing Overview

    NASA Technical Reports Server (NTRS)

    Byrnes, Ray

    2007-01-01

    A general overview of the USGS land remote sensing program is presented. The contents include: 1) Brief overview of USGS land remote sensing program; 2) Highlights of JACIE work at USGS; 3) Update on NASA/USGS Landsat Data Continuity Mission; and 4) Notes on alternative data sources.

  15. Frontal cerebral cortex blood flow, oxygen delivery and oxygenation during normoxic and hypoxic exercise in athletes

    PubMed Central

    Vogiatzis, Ioannis; Louvaris, Zafeiris; Habazettl, Helmut; Athanasopoulos, Dimitris; Andrianopoulos, Vasilis; Cherouveim, Evgenia; Wagner, Harrieth; Roussos, Charis; Wagner, Peter D; Zakynthinos, Spyros

    2011-01-01

    Abstract During maximal hypoxic exercise, a reduction in cerebral oxygen delivery may constitute a signal to the central nervous system to terminate exercise. We investigated whether the rate of increase in frontal cerebral cortex oxygen delivery is limited in hypoxic compared to normoxic exercise. We assessed frontal cerebral cortex blood flow using near-infrared spectroscopy and the light-absorbing tracer indocyanine green dye, as well as frontal cortex oxygen saturation ( %) in 11 trained cyclists during graded incremental exercise to the limit of tolerance (maximal work rate, WRmax) in normoxia and acute hypoxia (inspired O2 fraction (), 0.12). In normoxia, frontal cortex blood flow and oxygen delivery increased (P < 0.05) from baseline to sub-maximal exercise, reaching peak values at near-maximal exercise (80% WRmax: 287 ± 9 W; 81 ± 23% and 75 ± 22% increase relative to baseline, respectively), both leveling off thereafter up to WRmax (382 ± 10 W). Frontal cortex % did not change from baseline (66 ± 3%) throughout graded exercise. During hypoxic exercise, frontal cortex blood flow increased (P = 0.016) from baseline to sub-maximal exercise, peaking at 80% WRmax (213 ± 6 W; 60 ± 15% relative increase) before declining towards baseline at WRmax (289 ± 5 W). Despite this, frontal cortex oxygen delivery remained unchanged from baseline throughout graded exercise, being at WRmax lower than at comparable loads (287 ± 9 W) in normoxia (by 58 ± 12%; P = 0.01). Frontal cortex % fell from baseline (58 ± 2%) on light and moderate exercise in parallel with arterial oxygen saturation, but then remained unchanged to exhaustion (47 ± 1%). Thus, during maximal, but not light to moderate, exercise frontal cortex oxygen delivery is limited in hypoxia compared to normoxia. This limitation could potentially constitute the signal to limit maximal exercise capacity in hypoxia. PMID:21727220

  16. Plastids and gravitropic sensing

    NASA Technical Reports Server (NTRS)

    Sack, F. D.

    1997-01-01

    Data and theories about the identity of the mass that acts in gravitropic sensing are reviewed. Gravity sensing may have evolved several times in plants and algae in processes such as gravitropism of organs and tip-growing cells, gravimorphism, gravitaxis, and the regulation of cytoplasmic streaming in internodal cells of Chara. In the latter and in gravitaxis, the mass of the entire cell may function in sensing. But gravitropic sensing appears to rely upon the mass of amyloplasts that sediment since (i) the location of cells with sedimentation is highly regulated, (ii) such cells contain other morphological specializations favoring sedimentation, (iii) sedimentation always correlates with gravitropic competence in wild-type plants, (iv) magnetophoretic movement of rootcap amyloplasts mimics gravitropism, and (v) starchless and intermediate starch mutants show reduced gravitropic sensitivity. The simplest interpretation of these data is that gravitropic sensing is plastid-based.

  17. Sensing land pollution.

    NASA Technical Reports Server (NTRS)

    Bowden, L. W.

    1971-01-01

    Land pollution is described in numerous ways by various societies. Pollutants of land are material by-products of human activity and range from environmentally ineffective to positively toxic. The pollution of land by man is centuries old and correlates directly with economy, technology and population. In order to remotely sense land pollution, standards or thresholds must be established. Examples of the potential for sensing land pollution and quality are presented. The technological capabilities for remotely sensed land quality is far advanced over the judgment on how to use the sensed data. Until authoritative and directive decisions on land pollution policy are made, sensing of pollutants will be a random, local and academic affair.

  18. Venous oxygen saturation.

    PubMed

    Hartog, Christiane; Bloos, Frank

    2014-12-01

    Early detection and rapid treatment of tissue hypoxia are important goals. Venous oxygen saturation is an indirect index of global oxygen supply-to-demand ratio. Central venous oxygen saturation (ScvO2) measurement has become a surrogate for mixed venous oxygen saturation (SvO2). ScvO2 is measured by a catheter placed in the superior vena cava. After results from a single-center study suggested that maintaining ScvO2 values >70% might improve survival rates in septic patients, international practice guidelines included this target in a bundle strategy to treat early sepsis. However, a recent multicenter study with >1500 patients found that the use of central hemodynamic and ScvO2 monitoring did not improve long-term survival when compared to the clinical assessment of the adequacy of circulation. It seems that if sepsis is recognized early, a rapid initiation of antibiotics and adequate fluid resuscitation are more important than measuring venous oxygen saturation.

  19. Optical oxygen concentration monitor

    DOEpatents

    Kebabian, P.

    1997-07-22

    A system for measuring and monitoring the concentration of oxygen uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to one of oxygen`s A-band absorption lines. In a preferred embodiment, the argon line is split into sets of components of shorter and longer wavelengths by a magnetic field of approximately 2,000 Gauss that is parallel to the light propagation from the lamp. The longer wavelength components are centered on an absorption line of oxygen and thus readily absorbed, and the shorter wavelength components are moved away from that line and minimally absorbed. A polarization modulator alternately selects the set of the longer wavelength, or upshifted, components or the set of the shorter wavelength, or downshifted, components and passes the selected set to an environment of interest. After transmission over a path through that environment, the transmitted optical flux of the argon line varies as a result of the differential absorption. The system then determines the concentration of oxygen in the environment based on the changes in the transmitted optical flux between the two sets of components. In alternative embodiments modulation is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to either the emitting plasma of the lamp or the environment of interest. 4 figs.

  20. Atomic oxygen stimulated outgassing

    NASA Technical Reports Server (NTRS)

    Linton, Roger C.; Reynolds, John M.

    1991-01-01

    The passive Long Duration Exposure Facility (LDEF) Experiment A0034, Atomic Oxygen Simulated Outgassing, consisted of two identical one-sixth tray modules, exposing selected thermal control coatings to atomic oxygen and the combined space environment on the leading edge and, for reference, to the relative wake environment on the trailing edge. Optical mirrors were included adjacent to the thermal coatings for deposition of outgassing products. Ultraviolet grade windows and metal covers were provided for additional assessment of the effects of the various environmental factors. Preliminary results indicate that orbital atomic oxygen is both a degrading and a optically restorative factor in the thermo-optical properties of selected thermal coatings. There is evidence of more severe optical degradation on collector mirrors adjacent to coatings that were exposed to the RAM-impinging atomic oxygen. This evidence of atomic oxygen stimulated outgassing is discussed in relation to alternative factors that could affect degradation. The general effects of the space environment on the experiment hardware as well as the specimens are discussed.

  1. Hydrogen Sulfide as an Oxygen Sensor

    PubMed Central

    2015-01-01

    Abstract Significance Although oxygen (O2)-sensing cells and tissues have been known for decades, the identity of the O2-sensing mechanism has remained elusive. Evidence is accumulating that O2-dependent metabolism of hydrogen sulfide (H2S) is this enigmatic O2 sensor. Recent Advances The elucidation of biochemical pathways involved in H2S synthesis and metabolism have shown that reciprocal H2S/O2 interactions have been inexorably linked throughout eukaryotic evolution; there are multiple foci by which O2 controls H2S inactivation, and the effects of H2S on downstream signaling events are consistent with those activated by hypoxia. H2S-mediated O2 sensing has been demonstrated in a variety of O2-sensing tissues in vertebrate cardiovascular and respiratory systems, including smooth muscle in systemic and respiratory blood vessels and airways, carotid body, adrenal medulla, and other peripheral as well as central chemoreceptors. Critical Issues Information is now needed on the intracellular location and stoichometry of these signaling processes and how and which downstream effectors are activated by H2S and its metabolites. Future Directions Development of specific inhibitors of H2S metabolism and effector activation as well as cellular organelle-targeted compounds that release H2S in a time- or environmentally controlled way will not only enhance our understanding of this signaling process but also provide direction for future therapeutic applications. Antioxid. Redox Signal. 22, 377–397. “Nothing in Biology Makes Sense Except in the Light of Evolution” —Theodosius Dobzhansky (29) PMID:24801248

  2. Activated platelet chemiluminescence and presence of CD45+ platelets in patients with acute myocardial infarction.

    PubMed

    Gabbasov, Zufar; Ivanova, Oxana; Kogan-Yasny, Victor; Ryzhkova, Evgeniya; Saburova, Olga; Vorobyeva, Inna; Vasilieva, Elena

    2014-01-01

    It has been found that in 15% of acute myocardial infarction patients' platelets generate reactive oxygen species that can be detected with luminol-enhanced chemiluminescence of platelet-rich plasma within 8-10 days after acute myocardial infarction. This increase in generate reactive oxygen species production coincides with the emergence of CD45(+) platelets. The ability of platelets to carry surface leukocyte antigen implies their participation in exchange of specific proteins in the course of acute myocardial infarction. Future studies of CD45(+) platelets in peripheral blood of acute myocardial infarction patients in association with generate reactive oxygen species production may provide a new insight into the complex mechanisms of cell-cell interactions associated with acute myocardial infarction.

  3. Structural analysis of an oxygen-regulated diguanylate cyclase.

    PubMed

    Tarnawski, Miroslaw; Barends, Thomas R M; Schlichting, Ilme

    2015-11-01

    Cyclic di-GMP is a bacterial second messenger that is involved in switching between motile and sessile lifestyles. Given the medical importance of biofilm formation, there has been increasing interest in understanding the synthesis and degradation of cyclic di-GMPs and their regulation in various bacterial pathogens. Environmental cues are detected by sensing domains coupled to GGDEF and EAL or HD-GYP domains that have diguanylate cyclase and phosphodiesterase activities, respectively, producing and degrading cyclic di-GMP. The Escherichia coli protein DosC (also known as YddV) consists of an oxygen-sensing domain belonging to the class of globin sensors that is coupled to a C-terminal GGDEF domain via a previously uncharacterized middle domain. DosC is one of the most strongly expressed GGDEF proteins in E. coli, but to date structural information on this and related proteins is scarce. Here, the high-resolution structural characterization of the oxygen-sensing globin domain, the middle domain and the catalytic GGDEF domain in apo and substrate-bound forms is described. The structural changes between the iron(III) and iron(II) forms of the sensor globin domain suggest a mechanism for oxygen-dependent regulation. The structural information on the individual domains is combined into a model of the dimeric DosC holoprotein. These findings have direct implications for the oxygen-dependent regulation of the activity of the cyclase domain.

  4. Aircraft Oxygen Generation

    DTIC Science & Technology

    2012-02-01

    toluene, benzene), halogenated hydrocarbons (e.g., trichloroethylene, freons), and other gases (e.g., hydrogen cyanide ) was assessed. A Neurotoxicity...TO-11 to quantify aldehydes. Direct reading instruments were also utilized to measure certain contaminants, such as carbon monoxide, cyanide , and...including metabolic toxicants such as carbon monoxide, cyanide , or organophosphates, have been measured at concentrations associated with acute CNS

  5. Evidence for Direct Control of Virulence and Defense Gene Circuits by the Pseudomonas aeruginosa Quorum Sensing Regulator, MvfR

    PubMed Central

    Maura, Damien; Hazan, Ronen; Kitao, Tomoe; Ballok, Alicia E.; Rahme, Laurence G.

    2016-01-01

    Pseudomonas aeruginosa defies eradication by antibiotics and is responsible for acute and chronic human infections due to a wide variety of virulence factors. Currently, it is believed that MvfR (PqsR) controls the expression of many of these factors indirectly via the pqs and phnAB operons. Here we provide strong evidence that MvfR may also bind and directly regulate the expression of additional 35 loci across the P. aeruginosa genome, including major regulators and virulence factors, such as the quorum sensing (QS) regulators lasR and rhlR, and genes involved in protein secretion, translation, and response to oxidative stress. We show that these anti-oxidant systems, AhpC-F, AhpB-TrxB2 and Dps, are critical for P. aeruginosa survival to reactive oxygen species and antibiotic tolerance. Considering that MvfR regulated compounds generate reactive oxygen species, this indicates a tightly regulated QS self-defense anti-poisoning system. These findings also challenge the current hierarchical regulation model of P. aeruginosa QS systems by revealing new interconnections between them that suggest a circular model. Moreover, they uncover a novel role for MvfR in self-defense that favors antibiotic tolerance and cell survival, further demonstrating MvfR as a highly desirable anti-virulence target. PMID:27678057

  6. Iron, oxygen, and the pulmonary circulation

    PubMed Central

    2015-01-01

    The human pulmonary vasculature vasoconstricts in response to a reduction in alveolar oxygen tension, a phenomenon termed hypoxic pulmonary vasoconstriction (HPV). This review describes the time course of this behavior, which occurs in distinct phases, and then explores the importance for HPV of the hypoxia-inducible factor (HIF) pathway. Next, the HIF-hydroxylase enzymes that act as molecular oxygen sensors within the HIF pathway are discussed. These enzymes are particularly sensitive to intracellular iron availability, which confers iron-sensing properties on the HIF pathway. Human studies of iron chelation and supplementation are then reviewed. These demonstrate that the iron sensitivity of the HIF pathway evident from in vitro experiments is relevant to human pulmonary vascular physiology. Next, the importance of iron status in high-altitude illness and chronic cardiopulmonary disease is explored, and the therapeutic potential of intravenous iron discussed. The review concludes by highlighting some further complexities that arise from interactions between the HIF pathway and other intracellular iron-sensing mechanisms. PMID:26066825

  7. Monolithic solid electrolyte oxygen pump

    DOEpatents

    Fee, Darrell C.; Poeppel, Roger B.; Easler, Timothy E.; Dees, Dennis W.

    1989-01-01

    A multi-layer oxygen pump having a one-piece, monolithic ceramic structure affords high oxygen production per unit weight and volume and is thus particularly adapted for use as a portable oxygen supply. The oxygen pump is comprised of a large number of small cells on the order of 1-2 millimeters in diameter which form the walls of the pump and which are comprised of thin, i.e., 25-50 micrometers, ceramic layers of cell components. The cell components include an air electrode, an oxygen electrode, an electrolyte and interconnection materials. The cell walls form the passages for input air and for exhausting the oxygen which is transferred from a relatively dilute gaseous mixture to a higher concentration by applying a DC voltage across the electrodes so as to ionize the oxygen at the air electrode, whereupon the ionized oxygen travels through the electrolyte and is converted to oxygen gas at the oxygen electrode.

  8. Beriberi Induced Cardiomyopathy Requiring Salvage Venoarterial Extracorporeal Membrane Oxygenation

    PubMed Central

    Patel, Samir; Kothari, Sorabh; Denk, Jennifer

    2016-01-01

    Beriberi refers to a constellation of symptoms caused primarily by thiamine (vitamin B1) deficiency. An acute and fulminant presentation of this rare condition has been described in the literature as “Shoshin” beriberi which is characterized by catastrophic cardiovascular collapse. Early recognition and treatment lead to dramatic improvements of symptoms. We present a case of thiamine deficiency-induced acute heart failure in a malnourished patient leading to cardiac arrest necessitating VA-ECMO (venoarterial extracorporeal membrane oxygenation) with improvement in heart function secondary to thiamine administration. PMID:28050289

  9. Neurological oxygen toxicity.

    PubMed

    Farmery, Scott; Sykes, Oliver

    2012-10-01

    SCUBA diving has several risks associated with it from breathing air under pressure--nitrogen narcosis, barotrauma and decompression sickness (the bends). Trimix SCUBA diving involves regulating mixtures of nitrogen, oxygen and helium in an attempt to overcome the risks of narcosis and decompression sickness during deep dives, but introduces other potential hazards such as hypoxia and oxygen toxicity convulsions. This study reports on a seizure during the ascent phase, its potential causes and management and discusses the hazards posed to the diver and his rescuer by an emergency ascent to the surface.

  10. Pentoxifylline Treatment in Acute Pancreatitis (AP)

    ClinicalTrials.gov

    2016-09-14

    Acute Pancreatitis (AP); Gallstone Pancreatitis; Alcoholic Pancreatitis; Post-ERCP/Post-procedural Pancreatitis; Trauma Acute Pancreatitis; Hypertriglyceridemia Acute Pancreatitis; Idiopathic (Unknown) Acute Pancreatitis; Medication Induced Acute Pancreatitis; Cancer Acute Pancreatitis; Miscellaneous (i.e. Acute on Chronic Pancreatitis)

  11. [The sense of taste].

    PubMed

    Rabinerson, David; Horovitz, Eran; Beloosesky, Yeshayahoo

    2006-08-01

    The taste sense is one of the five human senses. It is essential to our survival because it enables the individual the choice of correct food, which, in turn, is crucial for one's existence, maintenance and function. This is a complicated chemical sense, which operates in conjunction with other senses such as vision, smell and touch, and is also associated with the operation of temperature and consistency receptors. There are five basic tastes: bitter, sweet, sour, salty and "fleshy" (umami), each of which has a role in food selection, being responsible for the recognition of certain chemicals, which may be either necessary or dangerous to our body. The taste cell is located in the taste buds, which, in turn, are situated in the tongue, oral cavity and the proximal third of the esophagus. This translates the chemical signal of tastants in food to electrical stimulation that transfers the signal to higher processing centers in the brain, in a process called transduction, which is explained in this review. Disturbances in the taste sense, as well as effects of industrial exposure on this sense are also described. The accumulated knowledge about the taste sense might enable future breakthroughs in the processed food industry.

  12. High-flow nasal cannula oxygen therapy in adults.

    PubMed

    Nishimura, Masaji

    2015-01-01

    High-flow nasal cannula (HFNC) oxygen therapy comprises an air/oxygen blender, an active humidifier, a single heated circuit, and a nasal cannula. It delivers adequately heated and humidified medical gas at up to 60 L/min of flow and is considered to have a number of physiological effects: reduction of anatomical dead space, PEEP effect, constant fraction of inspired oxygen, and good humidification. While there have been no big randomized clinical trials, it has been gaining attention as an innovative respiratory support for critically ill patients. Most of the available data has been published in the neonatal field. Evidence with critically ill adults are poor; however, physicians apply it to a variety of patients with diverse underlying diseases: hypoxemic respiratory failure, acute exacerbation of chronic obstructive pulmonary disease, post-extubation, pre-intubation oxygenation, sleep apnea, acute heart failure, patients with do-not-intubate order, and so on. Many published reports suggest that HFNC decreases breathing frequency and work of breathing and reduces needs of escalation of respiratory support in patients with diverse underlying diseases. Some important issues remain to be resolved, such as its indication, timing of starting and stopping HFNC, and escalating treatment. Despite these issues, HFNC oxygen therapy is an innovative and effective modality for the early treatment of adults with respiratory failure with diverse underlying diseases.

  13. [Hemoglobin solutions: volume replacement or oxygen therapy?].

    PubMed

    Standl, T

    1998-11-01

    The development of haemoglobin solutions has progressed significantly in the last 15 years because of a perceived short fall in allogeneic blood within the next decades and increased concern about transmitted infectious diseases. Animal studies have shown that modern highly purified and chemically modified haemoglobin preparations are free of toxic side effects, provide adequate volume replacement and have vasoconstrictive effects that enhance systemic vascular resistance and mean arterial pressures after haemorrhage and in models of nearly complete blood replacement. Microcirculatory effects of haemoglobin-based oxygen carriers are dependent on the respective organ and species in which they are applied and on their degree of purification and chemical modification. Because of different physico-chemical properties in comparison with red cells, haemoglobin solutions provide sufficient tissue oxygenation in areas with critically restricted perfusion even when applied in small doses. First studies in volunteers and patients showed efficacy and tolerability of different newly developed haemoglobin solutions during acute normovolaemic haemodilution and in perioperative blood replacement. However, only little information exists to date in terms of metabolism of haemoglobin preparations and their potential immunogenicity and immunosuppressive side effects. Technical problems with the clinical use of haemoglobin solutions arise because of interference of plasma haemoglobin with routine laboratory tests and oximetry. Future indications for haemoglobin solutions as an oxygen therapeutic allow for application of small doses of such preparations and may help to avoid major technical problems. More clinical studies have to be undertaken to confirm the effectivity and safety of the different haemoglobin solutions and to find out the optimal indications beyond acute preclinical and perioperative blood replacement.

  14. Remote sensing program

    NASA Technical Reports Server (NTRS)

    Philipson, W. R. (Principal Investigator)

    1983-01-01

    Built on Cornell's thirty years of experience in aerial photographic studies, the NASA-sponsored remote sensing program strengthened instruction and research in remote sensing, established communication links within and beyond the university community, and conducted research projects for or with town, county, state, federal, and private organizations in New York State. The 43 completed applied research projects are listed as well as 13 spinoff grants/contracts. The curriculum offered, consultations provided, and data processing facilities available are described. Publications engendered are listed including the thesis of graduates in the remote sensing program.

  15. Micro environmental sensing device

    DOEpatents

    Polosky, Marc A.; Lukens, Laurance L.

    2006-05-02

    A microelectromechanical (MEM) acceleration switch is disclosed which includes a proof mass flexibly connected to a substrate, with the proof mass being moveable in a direction substantially perpendicular to the substrate in response to a sensed acceleration. An electrode on the proof mass contacts one or more electrodes located below the proof mass to provide a switch closure in response to the sensed acceleration. Electrical latching of the switch in the closed position is possible with an optional latching electrode. The MEM acceleration switch, which has applications for use as an environmental sensing device, can be fabricated using micromachining.

  16. Peroxide-Sensing Transcriptional Regulators in Bacteria

    PubMed Central

    Mongkolsuk, Skorn

    2012-01-01

    The ability to maintain intracellular concentrations of toxic reactive oxygen species (ROS) within safe limits is essential for all aerobic life forms. In bacteria, as well as other organisms, ROS are produced during the normal course of aerobic metabolism, necessitating the constitutive expression of ROS scavenging systems. However, bacteria can also experience transient high-level exposure to ROS derived either from external sources, such as the host defense response, or as a secondary effect of other seemingly unrelated environmental stresses. Consequently, transcriptional regulators have evolved to sense the levels of ROS and coordinate the appropriate oxidative stress response. Three well-studied examples of these are the peroxide responsive regulators OxyR, PerR, and OhrR. OxyR and PerR are sensors of primarily H2O2, while OhrR senses organic peroxide (ROOH) and sodium hypochlorite (NaOCl). OxyR and OhrR sense oxidants by means of the reversible oxidation of specific cysteine residues. In contrast, PerR senses H2O2 via the Fe-catalyzed oxidation of histidine residues. These transcription regulators also influence complex biological phenomena, such as biofilm formation, the evasion of host immune responses, and antibiotic resistance via the direct regulation of specific proteins. PMID:22797754

  17. Peroxide-sensing transcriptional regulators in bacteria.

    PubMed

    Dubbs, James M; Mongkolsuk, Skorn

    2012-10-01

    The ability to maintain intracellular concentrations of toxic reactive oxygen species (ROS) within safe limits is essential for all aerobic life forms. In bacteria, as well as other organisms, ROS are produced during the normal course of aerobic metabolism, necessitating the constitutive expression of ROS scavenging systems. However, bacteria can also experience transient high-level exposure to ROS derived either from external sources, such as the host defense response, or as a secondary effect of other seemingly unrelated environmental stresses. Consequently, transcriptional regulators have evolved to sense the levels of ROS and coordinate the appropriate oxidative stress response. Three well-studied examples of these are the peroxide responsive regulators OxyR, PerR, and OhrR. OxyR and PerR are sensors of primarily H(2)O(2), while OhrR senses organic peroxide (ROOH) and sodium hypochlorite (NaOCl). OxyR and OhrR sense oxidants by means of the reversible oxidation of specific cysteine residues. In contrast, PerR senses H(2)O(2) via the Fe-catalyzed oxidation of histidine residues. These transcription regulators also influence complex biological phenomena, such as biofilm formation, the evasion of host immune responses, and antibiotic resistance via the direct regulation of specific proteins.

  18. Reversible oxygen scavenging at room temperature using electrochemically reduced titanium oxide nanotubes

    NASA Astrophysics Data System (ADS)

    Close, Thomas; Tulsyan, Gaurav; Diaz, Carlos A.; Weinstein, Steven J.; Richter, Christiaan

    2015-05-01

    A material capable of rapid, reversible molecular oxygen uptake at room temperature is desirable for gas separation and sensing, for technologies that require oxygen storage and oxygen splitting such as fuel cells (solid-oxide fuel cells in particular) and for catalytic applications that require reduced oxygen species (such as removal of organic pollutants in water and oil-spill remediation). To date, however, the lowest reported temperature for a reversible oxygen uptake material is in the range of 200-300 °C, achieved in the transition metal oxides SrCoOx (ref. 1) and LuFe2O4+x (ref. 2) via thermal cycling. Here, we report rapid and reversible oxygen scavenging by TiO2-x nanotubes at room temperature. The uptake and release of oxygen is accomplished by an electrochemical rather than a standard thermal approach. We measure an oxygen uptake rate as high as 14 mmol O2 g-1 min-1, ˜2,400 times greater than commercial, irreversible oxygen scavengers. Such a fast oxygen uptake at a remarkably low temperature suggests a non-typical mechanistic pathway for the re-oxidation of TiO2-x. Modelling the diffusion of oxygen, we show that a likely pathway involves ‘exceptionally mobile’ interstitial oxygen produced by the oxygen adsorption and decomposition dynamics, recently observed on the surface of anatase.

  19. Extracorporeal membrane oxygenation for extremely complicated scrub typhus.

    PubMed

    Oh, Won-Sup; Yie, Kilsoo

    2012-01-01

    Scrub typhus is a mite-borne disease caused by Orientia tsutsugamushi. Although early diagnosis and appropriate antibiotic therapy improve the prognosis for the majority of patients, life-threatening complications are not uncommon. Here, we present a case of successfully performed veno-veno type extracorporeal membrane oxygenation for scrub typhus-induced complications, including acute respiratory distress syndrome, sudden cardiac arrest, and multiorgan dysfunction. To our knowledge, this is the first case report of successful extracorporeal membrane oxygenation in complicated scrub typhus.

  20. Bright, “clickable” porphyrins enable visualization of oxygenation under ambient light**

    PubMed Central

    Roussakis, Emmanuel; Li, Zongxi; Nowell, Nicholas H.; Nichols, Alexander J.

    2015-01-01

    A new group of “clickable” and brightly emissive metalloporphyrins has been developed for the visualization of oxygenation under ambient light by eye. These alkynyl-terminated compounds permit the rapid and facile synthesis of oxygen-sensing dendrimers through azide-alkyne click chemistry. With absorption maxima overlapping with the wavelengths of common commercial laser sources, they are readily applicable to biomedical imaging of tissue oxygenation. An efficient synthetic methodology, featuring the stable trimethylacetyl (pivaloyl) protecting group, is described for their preparation. A paint-on liquid bandage containing a new, click-synthesized porphyrin dendrimer has been used to map oxygenation across an ex vivo porcine skin burn model. A group of easy-to-use, mass-producible sensors should spur major advances in both clinical use and basic research in the field of oxygen sensing. PMID:26510549