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Liu S, Li R, Ni X, Cai Z, Zhang R, Sun X, Quock RM, Xu W. Perfluorocarbon-facilitated CNS oxygen toxicity in rats: reversal by edaravone. Brain Res 2012; 1471:56-65. [PMID: 22781141 DOI: 10.1016/j.brainres.2012.06.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Revised: 06/12/2012] [Accepted: 06/28/2012] [Indexed: 12/31/2022]
Abstract
Perfluorocarbon (PFC) has been hypothesized to potentially increase the risk of central nervous system oxygen toxicity (CNS-OT) under hyperbaric oxygen (HBO) conditions. However, little is known about the effects, mechanism and prevention of PFC-facilitated CNS-OT. A rat model of CNS-OT was used to evaluate the effects of intravenously-administered PFC emulsion. The electroencephalogram (EEG) was recorded during treatment with HBO(2) at 6.0 ATA in the presence and absence of PFC. Concentrations of malondialdehyde (MDA), nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) in the brain cortex and hippocampus were quantified. Changes in the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and NO synthase (NOS) in the brain cortex and hippocampus were also determined. Edaravone, a potent antioxidant, was used to prevent PFC-facilitated CNS-OT. The results showed that after PFC administration, the latency to first electrical discharge in EEG was significantly shortened; MDA, H(2)O(2), NO levels and NOS activity increased; and SOD, GPx and CAT activities decreased. Edaravone effectively protected against CNS-OT and the adverse effects of PFC. The results clearly demonstrate that PFC administered before HBO(2) would promote the occurrence of CNS-OT, and edaravone could serve as a promising chemoprophylactic agent to prevent CNS-OT.
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Affiliation(s)
- Shulin Liu
- Department of Diving Medicine, the Second Military Medical University, Shanghai 200433, P.R. China
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52
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Freiberger JJ, Padilla-Burgos R, McGraw T, Suliman HB, Kraft KH, Stolp BW, Moon RE, Piantadosi CA. What Is the Role of Hyperbaric Oxygen in the Management of Bisphosphonate-Related Osteonecrosis of the Jaw: A Randomized Controlled Trial of Hyperbaric Oxygen as an Adjunct to Surgery and Antibiotics. J Oral Maxillofac Surg 2012; 70:1573-83. [DOI: 10.1016/j.joms.2012.04.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/06/2012] [Accepted: 04/06/2012] [Indexed: 12/28/2022]
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Demchenko IT, Moskvin AN, Krivchenko AI, Piantadosi CA, Allen BW. Nitric oxide-mediated central sympathetic excitation promotes CNS and pulmonary O₂ toxicity. J Appl Physiol (1985) 2012; 112:1814-23. [PMID: 22442027 PMCID: PMC3379151 DOI: 10.1152/japplphysiol.00902.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 03/16/2012] [Indexed: 01/29/2023] Open
Abstract
In hyperbaric oxygen (HBO(2)) at or above 3 atmospheres absolute (ATA), autonomic pathways link central nervous system (CNS) oxygen toxicity to pulmonary damage, possibly through a paradoxical and poorly characterized relationship between central nitric oxide production and sympathetic outflow. To investigate this possibility, we assessed sympathetic discharges, catecholamine release, cardiopulmonary hemodynamics, and lung damage in rats exposed to oxygen at 5 or 6 ATA. Before HBO(2) exposure, either a selective inhibitor of neuronal nitric oxide synthase (NOS) or a nonselective NOS inhibitor was injected directly into the cerebral ventricles to minimize effects on the lung, heart, and peripheral circulation. Experiments were performed on both anesthetized and conscious rats to differentiate responses to HBO(2) from the effects of anesthesia. EEG spikes, markers of CNS toxicity in anesthetized animals, were approximately four times as likely to develop in control rats than in animals with central NOS inhibition. In inhibitor-treated animals, autonomic discharges, cardiovascular pressures, catecholamine release, and cerebral blood flow all remained below baseline throughout exposure to HBO(2). In control animals, however, initial declines in these parameters were followed by significant increases above their baselines. In awake animals, central NOS inhibition significantly decreased the incidence of clonic-tonic convulsions or delayed their onset, compared with controls. The novel findings of this study are that NO produced by nNOS in the periventricular regions of the brain plays a critical role in the events leading to both CNS toxicity in HBO(2) and to the associated sympathetic hyperactivation involved in pulmonary injury.
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Affiliation(s)
- Ivan T Demchenko
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC 27710, USA
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Samuni Y, Samuni U, Goldstein S. The mechanism underlying nitroxyl and nitric oxide formation from hydroxamic acids. Biochim Biophys Acta Gen Subj 2012; 1820:1560-6. [PMID: 22634736 DOI: 10.1016/j.bbagen.2012.05.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 04/19/2012] [Accepted: 05/17/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND The pharmacological effects of hydroxamic acids (RC(O)NHOH, HX) are partially attributed to their ability to serve as HNO and/or NO donors under oxidative stress. Given the development and use of HXs as therapeutic agents, elucidation of the oxidation mechanism is needed for more educated selection of HX-based drugs. METHODS Acetohydroxamic and glycine-hydroxamic acids were oxidized at pH 7.0 by a continuous flux of radiolytically generated (·)OH or by metmyoglobin and H(2)O(2) reactions system. Gas chromatography and spectroscopic methods were used to monitor the accumulation of N(2)O, N(2), nitrite and hydroxylamine. RESULTS Oxidation of HXs by (·)OH under anoxia yields N(2)O, but not nitrite, N(2) or hydroxylamine. Upon the addition of H(2)O(2) to solutions containing HX and metmyoglobin, which is instantaneously and continuously converted into compound II, nitrite and, to a lesser extent, N(2)O are accumulated under both anoxia and normoxia. CONCLUSIONS Oxidation of HXs under anoxia by a continuous flux of (·)OH, which solely oxidizes the hydroxamate moiety to RC(O)NHO(·), forms HNO. This observation implies that bimolecular decomposition of RC(O)NHO(·) competes efficiently with unimolecular decomposition processes such as internal disproportionation, hydrolysis or homolysis. Oxidation by metmyoglobin/H(2)O(2) involves relatively mild oxidants (compounds I and II). Compound I reacts with HX forming RC(O)NHO(·) and compound II, which oxidizes HX, RC(O)NHO(·), HNO and NO. The latter reaction is the main source of nitrite. GENERAL SIGNIFICANCE HXs under oxidative stress release HNO, but can be considered as NO-donors provided that HNO oxidation is more efficient than its reaction with other biological targets.
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Affiliation(s)
- Yuval Samuni
- Oral and Maxillofacial Surgery, The Brazilai Medical Center, Ashkelon, Israel
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Dutka TL, Verburg E, Larkins N, Hortemo KH, Lunde PK, Sejersted OM, Lamb GD. ROS-mediated decline in maximum Ca2+-activated force in rat skeletal muscle fibers following in vitro and in vivo stimulation. PLoS One 2012; 7:e35226. [PMID: 22629297 PMCID: PMC3358267 DOI: 10.1371/journal.pone.0035226] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/13/2012] [Indexed: 11/22/2022] Open
Abstract
We hypothesised that normal skeletal muscle stimulated intensely either in vitro or in situ would exhibit reactive oxygen species (ROS)-mediated contractile apparatus changes common to many pathophysiological conditions. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat were bubbled with 95% O2 and stimulated in vitro at 31°C to give isometric tetani (50 Hz for 0.5 s every 2 s) until maximum force declined to ≤30%. Skinned superficial slow-twitch fibers from the SOL muscles displayed a large reduction (∼41%) in maximum Ca2+-activated specific force (Fmax), with Ca2+-sensitivity unchanged. Fibers from EDL muscles were less affected. The decrease in Fmax in SOL fibers was evidently due to oxidation effects on cysteine residues because it was reversed if the reducing agent DTT was applied prior to activating the fiber. The GSH∶GSSG ratio was ∼3-fold lower in the cytoplasm of superficial fibers from stimulated muscle compared to control, confirming increased oxidant levels. The presence of Tempol and L-NAME during in vitro stimulation prevented reduction in Fmax. Skinned fibers from SOL muscles stimulated in vivo at 37°C with intact blood supply also displayed reduction in Fmax, though to a much smaller extent (∼12%). Thus, fibers from muscles stimulated even with putatively adequate O2 supply display a reversible oxidation-induced decrease in Fmax without change in Ca2+-sensitivity, consistent with action of peroxynitrite (or possibly superoxide) on cysteine residues of the contractile apparatus. Significantly, the changes closely resemble the contractile deficits observed in a range of pathophysiological conditions. These findings highlight how readily muscle experiences ROS-related deficits, and also point to potential difficulties when defining muscle performance and fatigue.
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Affiliation(s)
- Travis L Dutka
- Department of Zoology, La Trobe University, Melbourne, Australia.
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Lee JK, Sayers BC, Chun KS, Lao HC, Shipley-Phillips JK, Bonner JC, Langenbach R. Multi-walled carbon nanotubes induce COX-2 and iNOS expression via MAP kinase-dependent and -independent mechanisms in mouse RAW264.7 macrophages. Part Fibre Toxicol 2012; 9:14. [PMID: 22571318 PMCID: PMC3485091 DOI: 10.1186/1743-8977-9-14] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 05/09/2012] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Carbon nanotubes (CNTs) are engineered graphene cylinders with numerous applications in engineering, electronics and medicine. However, CNTs cause inflammation and fibrosis in the rodent lung, suggesting a potential human health risk. We hypothesized that multi-walled CNTs (MWCNTs) induce two key inflammatory enzymes in macrophages, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), through activation of extracellular signal-regulated kinases (ERK1,2). METHODS RAW264.7 macrophages were exposed to MWCNTs or carbon black nanoparticles (CBNPs) over a range of doses and time course. Uptake and subcellular localization of MWCNTs was visualized by transmission electron microscopy (TEM). Protein levels of COX-2, iNOS, and ERK1,2 (total ERK and phosphorylated ERK) were measured by Western blot analysis. Prostaglandin-E(2) (PGE(2)) and nitric oxide (NO) levels in cell supernatants were measured by ELISA and Greiss assay, respectively. RESULTS MWCNTs, but not CBNPs, induced COX-2 and iNOS in a time- and dose-dependent manner. COX-2 and iNOS induction by MWCNTs correlated with increased PGE(2) and NO production, respectively. MWCNTs caused ERK1,2 activation and inhibition of ERK1,2 (U0126) blocked MWCNT induction of COX-2 and PGE2 production, but did not reduce the induction of iNOS. Inhibition of iNOS (L-NAME) did not affect ERK1,2 activation, nor did L-NAME significantly decrease COX-2 induction by MWCNT. Nickel nanoparticles (NiNPs), which are present in MWCNTs as a residual catalyst, also induced COX-2 via ERK-1,2. However, a comparison of COX-2 induction by MWCNTs containing 4.5 and 1.8% Ni did not show a significant difference in ability to induce COX-2, indicating that characteristics of MWCNTs in addition to Ni content contribute to COX-2 induction. CONCLUSION This study identifies COX-2 and subsequent PGE(2) production, along with iNOS induction and NO production, as inflammatory mediators involved in the macrophage response to MWCNTs. Furthermore, our work demonstrates that COX-2 induction by MWCNTs in RAW264.7 macrophages is ERK1,2-dependent, while iNOS induction by MWCNTs is ERK1,2-independent. Our data also suggest contributory physicochemical factors other than residual Ni catalyst play a role in COX-2 induction to MWCNT.
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Affiliation(s)
- Jong Kwon Lee
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC 27709, USA
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Blood oxygenation using microbubble suspensions. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 41:571-8. [PMID: 22476882 DOI: 10.1007/s00249-012-0811-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 03/12/2012] [Accepted: 03/22/2012] [Indexed: 10/28/2022]
Abstract
Microbubbles have been used in a variety of fields and have unique properties, for example shrinking collapse, long lifetime, efficient gas solubility, a negatively charged surface, and the ability to produce free radicals. In medicine, microbubbles have been used mainly as diagnostic aids to scan various organs of the body, and they have recently been investigated for use in drug and gene delivery. However, there have been no reports of blood oxygenation by use of oxygen microbubble fluids without shell reagents. In this study, we demonstrated that nano or microbubbles can achieve oxygen supersaturation of fluids, and may be sufficiently small and safe for infusion into blood vessels. Although Po(2) increases in fluids resulting from use of microbubbles were inhibited by polar solvents, normal saline solution (NSS) was little affected. Thus, NSS is suitable for production of oxygen-rich fluid. In addition, oxygen microbubble NSS effectively improved hypoxic conditions in blood. Thus, use of oxygen microbubble (nanobubble) fluids is a potentially effective novel method for oxygenation of hypoxic tissues, for infection control, and for anticancer treatment.
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Abstract
The epithelial Na(+) channel (ENaC) and acid-sensitive ion channel (ASIC) branches of the ENaC/degenerin superfamily of cation channels have drawn increasing attention as potential therapeutic targets in a variety of diseases and conditions. Originally thought to be solely expressed in fluid absorptive epithelia and in neurons, it has become apparent that members of this family exhibit nearly ubiquitous expression. Therapeutic opportunities range from hypertension, due to the role of ENaC in maintaining whole body salt and water homeostasis, to anxiety disorders and pain associated with ASIC activity. As a physiologist intrigued by the fundamental mechanics of salt and water transport, it was natural that Dale Benos, to whom this series of reviews is dedicated, should have been at the forefront of research into the amiloride-sensitive sodium channel. The cloning of ENaC and subsequently the ASIC channels has revealed a far wider role for this channel family than was previously imagined. In this review, we will discuss the known and potential roles of ENaC and ASIC subunits in the wide variety of pathologies in which these channels have been implicated. Some of these, such as the role of ENaC in Liddle's syndrome are well established, others less so; however, all are related in that the fundamental defect is due to inappropriate channel activity.
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Affiliation(s)
- Yawar J Qadri
- Department of Physiology and Biophysics, University of Alabama at Birmingham, AL 35294, USA
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Bhandari V, Choo-Wing R, Harijith A, Sun H, Syed MA, Homer RJ, Elias JA. Increased hyperoxia-induced lung injury in nitric oxide synthase 2 null mice is mediated via angiopoietin 2. Am J Respir Cell Mol Biol 2012; 46:668-76. [PMID: 22227562 DOI: 10.1165/rcmb.2011-0074oc] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Supplemental oxygen is frequently prescribed. However, prolonged exposure to high concentrations of oxygen causes hyperoxic acute lung injury (HALI), which manifests as acute respiratory distress syndrome in adults and leads to bronchopulmonary dysplasia in newborns (NBs). Nitric oxide (NO), NO synthases (NOSs), and angiopoietin (Ang) 2 have been implicated in the pathogenesis of HALI. However, the mechanisms of the contributions of NOS/NO and the relationship(s) between NOS/NO and Ang2 have not been addressed. In addition, the relevance of these moieties in adults and NBs has not been evaluated. To address these issues, we compared the responses in hyperoxia of wild-type (NOS [+/+]) and NOS null (-/-) young adult and NB mice. When compared with NOS2(+/+) adult controls, NOS2(-/-) animals manifest exaggerated alveolar-capillary protein leak and premature death. These responses were associated with enhanced levels of structural cell death, enhanced expression of proapoptotic regulatory proteins, and Ang2. Importantly, silencing RNA knockdown of Ang2 decreased the levels of cell death and the expression of proapoptotic mediators. These effects were at least partially NOS2 specific, and were development dependent, because survival was similar in adult NOS3(+/+) and NOS3(-/-) mice and NB NOS2(+/+) and NOS2(-/-) mice, respectively. These studies demonstrate that NOS2 plays an important protective role in HALI in adult animals. They also demonstrate that this response is mediated, at least in part, by the ability of NOS2 to inhibit hyperoxia-induced Ang2 production and thereby decrease Ang2-induced tissue injury.
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Affiliation(s)
- Vineet Bhandari
- Division of Perinatal Medicine, Yale University School of Medicine, Department of Pediatrics, Children's Hospital, 20 York Street, New Haven, CT 06520-8057, USA.
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Eynan M, Tsitlovsky D, Batit L, Hochman A, Krinsky N, Abramovich A. Is glucose-6-phosphate dehydrogenase deficiency a risk factor for hyperbaric oxygen exposure? Eur J Appl Physiol 2011; 112:2549-56. [DOI: 10.1007/s00421-011-2229-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 10/27/2011] [Indexed: 10/15/2022]
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Venetsanou K, Fildissis G, Tokta R, Brinias C, Baltopoulos G. The role of nitric oxide in cellular response to hyperbaric conditions. Eur J Appl Physiol 2011; 112:677-87. [DOI: 10.1007/s00421-011-2027-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 05/23/2011] [Indexed: 12/21/2022]
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Consequences of hyperoxia and the toxicity of oxygen in the lung. Nurs Res Pract 2011; 2011:260482. [PMID: 21994818 PMCID: PMC3169834 DOI: 10.1155/2011/260482] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 03/29/2011] [Accepted: 04/04/2011] [Indexed: 11/18/2022] Open
Abstract
Oxygen (O(2)) is life essential but as a drug has a maximum positive biological benefit and accompanying toxicity effects. Oxygen is therapeutic for treatment of hypoxemia and hypoxia associated with many pathological processes. Pathophysiological processes are associated with increased levels of hyperoxia-induced reactive O(2) species (ROS) which may readily react with surrounding biological tissues, damaging lipids, proteins, and nucleic acids. Protective antioxidant defenses can become overwhelmed with ROS leading to oxidative stress. Activated alveolar capillary endothelium is characterized by increased adhesiveness causing accumulation of cell populations such as neutrophils, which are a source of ROS. Increased levels of ROS cause hyperpermeability, coagulopathy, and collagen deposition as well as other irreversible changes occurring within the alveolar space. In hyperoxia, multiple signaling pathways determine the pulmonary cellular response: apoptosis, necrosis, or repair. Understanding the effects of O(2) administration is important to prevent inadvertent alveolar damage caused by hyperoxia in patients requiring supplemental oxygenation.
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63
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A role of stretch-activated potassium currents in the regulation of uterine smooth muscle contraction. Acta Pharmacol Sin 2011; 32:758-64. [PMID: 21642947 DOI: 10.1038/aps.2011.62] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Rates of premature birth are alarming and threaten societies and healthcare systems worldwide. Premature labor results in premature birth in over 50% of cases. Preterm birth accounts for three-quarters of infant morbidity and mortality. Children that survive birth before 34 weeks gestation often face life-long disability. Current treatments for preterm labor are wanting. No treatment has been found to be generally effective and none are systematically evaluated beyond 48 h. New approaches to the treatment of preterm labor are desperately needed. Recent studies from our laboratory suggest that the uterine muscle is a unique compartment with regulation of uterine relaxation unlike that of other smooth muscles. Here we discuss recent evidence that the mechanically activated 2-pore potassium channel, TREK-1, may contribute to contraction-relaxation signaling in uterine smooth muscle and that TREK-1 gene variants associated with human labor and preterm labor may lead to a better understanding of preterm labor and its possible prevention.
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Lawson-Smith P, Jansen EC, Hyldegaard O. Cyanide intoxication as part of smoke inhalation--a review on diagnosis and treatment from the emergency perspective. Scand J Trauma Resusc Emerg Med 2011; 19:14. [PMID: 21371322 PMCID: PMC3058018 DOI: 10.1186/1757-7241-19-14] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 03/03/2011] [Indexed: 11/10/2022] Open
Abstract
This paper reviews the current literature on smoke inhalation injuries with special attention to the effects of hydrogen cyanide. It is assumed that cyanide poisoning is still an overlooked diagnosis in fire victims. Treatment against cyanide poisoning in the emergency setting should be given based on the clinical diagnosis only. Oxygen in combination with a recommended antidote should be given immediately, the first to reduce cellular hypoxia and the second to eliminate cyanide. A specific antidote is hydroxycobalamin, which can be given iv. and has few side effects.
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Affiliation(s)
- Pia Lawson-Smith
- Laboratory of Hyperbaric Medicine, Department of Anesthesia, Center of Head and Orthopaedics, University Hospital Rigshospitalet, Blegdamsvej, Copenhagen, Denmark.
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Nachuraju P, Friedman AJ, Friedman JM, Cabrales P. Exogenous nitric oxide prevents cardiovascular collapse during hemorrhagic shock. Resuscitation 2011; 82:607-13. [PMID: 21342744 DOI: 10.1016/j.resuscitation.2010.12.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 11/15/2010] [Accepted: 12/27/2010] [Indexed: 11/27/2022]
Abstract
This study investigated the systemic and microvascular hemodynamic changes related to increased nitric oxide (NO) availability following significant hemorrhage, made available by administration of NO releasing nanoparticles (NO-nps). Hemodynamic responses to hemorrhagic shock were studied in the hamster window chamber. Acute hemorrhage was induced by arterial controlled bleeding of 50% of blood volume, and the resulting hemodynamic parameters were followed over 90 min. Exogenous NO was administered in the form of NO-nps (5mg/kg suspended in 50 μl saline) 10 min following induced hemorrhage. Control groups received equal dose of NO free nanoparticles (Control-nps) and Vehicle solution. Animals treated with NO-nps partially maintained systemic and microvascular function during hypovolemic shock compared to animals treated with Control-nps or the Vehicle (50 μl saline). The continuous NO released by the NO-nps reverted arteriolar vasoconstriction, partially recovered both functional capillary density and microvascular blood flows. Additionally, NO supplementation post hemorrhage prevented cardiac decompensation, and thereby maintained and stabilized the heart rate. Paradoxically, the peripheral vasodilation induced by the NO-nps did not decrease blood pressure, and combined with NO's effects on vascular resistance, NO-nps promoted intravascular pressure redistribution and blood flow, avoiding tissue ischemia. Therefore, by increasing NO availability with NO-nps during hypovolemic shock, it is possible that cardiac stability and microvascular perfusion can be preserved, ultimately increasing survivability and local tissue viability, and reducing hemorrhagic shock sequelae. The relevance, stability, and efficacy of exogenous NO therapy in the form of NO-nps will potentially facilitate the intended use in battlefield and trauma situations.
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Affiliation(s)
- Parimala Nachuraju
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY, United States
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66
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Circulating oxidative stress status in dromedary camels infested with sarcoptic mange. Vet Res Commun 2010; 35:35-45. [DOI: 10.1007/s11259-010-9450-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2010] [Indexed: 11/26/2022]
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Freiberger JJ, Feldmeier JJ. Evidence Supporting the Use of Hyperbaric Oxygen in the Treatment of Osteoradionecrosis of the Jaw. J Oral Maxillofac Surg 2010; 68:1903-6. [DOI: 10.1016/j.joms.2010.02.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Accepted: 02/03/2010] [Indexed: 01/10/2023]
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Inhaled nitric oxide prevents 3-nitrotyrosine formation in the lungs of neonatal mice exposed to >95% oxygen. Lung 2010; 188:217-27. [PMID: 20237791 DOI: 10.1007/s00408-010-9235-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 03/02/2010] [Indexed: 10/19/2022]
Abstract
Inhaled nitric oxide is being evaluated as a preventative therapy for patients at risk for bronchopulmonary dysplasia (BPD). Nitric oxide (NO), in the presence of superoxide, forms peroxynitrite, which reacts with tyrosine residues on proteins to form 3-nitrotyrosine (3-NT). However, NO can also act as an antioxidant and was recently found to improve the oxidative balance in preterm infants. Thus, we tested the hypothesis that the addition of a therapeutically relevant concentration (10 ppm) of NO to a hyperoxic exposure would lead to decreased 3-NT formation in the lung. FVB mouse pups were exposed to either room air (21% O(2)) or >95% O(2) with or without 10 ppm NO within 24 h of birth. In the first set of studies, body weights and survival were monitored for 7 days, and exposure to >95% O(2) resulted in impaired weight gain and near 100% mortality by 7 days. However, the mortality occurred earlier in pups exposed to >95% O(2) + NO than in pups exposed to >95% O(2) alone. In a second set of studies, lungs were harvested at 72 h. Immunohistochemistry of the lungs at 72 h revealed that the addition of NO decreased alveolar, bronchial, and vascular 3-NT staining in pups exposed to both room air and hyperoxia. The lung nitrite levels were higher in animals exposed to >95% oxygen + NO than in animals exposed to >95% oxygen alone. The protein levels of myeloperoxidase, monocyte chemotactic protein-1, and intracellular adhesion molecule-1 were assessed after 72 h of exposure and found to be greatest in the lungs of pups exposed to >95% O(2). This hyperoxia-induced protein expression was significantly attenuated by the addition of 10 ppm NO. We propose that in the presence of >95% O(2), peroxynitrite formation results in protein nitration; however, adding excess NO to the >95% O(2) exposure prevents 3-NT formation by NO reacting with peroxynitrite to produce nitrite and NO(2). We speculate that the decreased protein nitration observed with the addition of NO may be a potential mechanism limiting hyperoxic lung injury.
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Utility of Hyperbaric Oxygen in Treatment of Bisphosphonate-Related Osteonecrosis of the Jaws. J Oral Maxillofac Surg 2009; 67:96-106. [DOI: 10.1016/j.joms.2008.12.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 12/08/2008] [Indexed: 01/08/2023]
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Pendergast DR, Lundgren CEG. The physiology and pathophysiology of the hyperbaric and diving environments. J Appl Physiol (1985) 2009; 106:274-5. [DOI: 10.1152/japplphysiol.91477.2008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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de Jonge E, Peelen L, Keijzers PJ, Joore H, de Lange D, van der Voort PHJ, Bosman RJ, de Waal RAL, Wesselink R, de Keizer NF. Association between administered oxygen, arterial partial oxygen pressure and mortality in mechanically ventilated intensive care unit patients. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2008; 12:R156. [PMID: 19077208 PMCID: PMC2646321 DOI: 10.1186/cc7150] [Citation(s) in RCA: 259] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 11/12/2008] [Accepted: 12/10/2008] [Indexed: 01/11/2023]
Abstract
INTRODUCTION The aim of this study was to investigate whether in-hospital mortality was associated with the administered fraction of oxygen in inspired air (FiO2) and achieved arterial partial pressure of oxygen (PaO2). METHODS This was a retrospective, observational study on data from the first 24 h after admission from 36,307 consecutive patients admitted to 50 Dutch intensive care units (ICUs) and treated with mechanical ventilation. Oxygenation data from all admission days were analysed in a subset of 3,322 patients in 5 ICUs. RESULTS Mean PaO2 and FiO2 in the first 24 h after ICU admission were 13.2 kPa (standard deviation (SD) 6.5) and 50% (SD 20%) respectively. Mean PaO2 and FiO2 from all admission days were 12.4 kPa (SD 5.5) and 53% (SD 18). Focusing on oxygenation in the first 24 h of admission, in-hospital mortality was shown to be linearly related to FiO2 value and had a U-shaped relationship with PaO2 (both lower and higher PaO2 values were associated with a higher mortality), independent of each other and of Simplified Acute Physiology Score (SAPS) II, age, admission type, reduced Glasgow Coma Scale (GCS) score, and individual ICU. Focusing on the entire ICU stay, in-hospital mortality was independently associated with mean FiO2 during ICU stay and with the lower two quintiles of mean PaO2 value during ICU stay. CONCLUSIONS Actually achieved PaO2 values in ICU patients in The Netherlands are higher than generally recommended in the literature. High FiO2, and both low PaO2 and high PaO2 in the first 24 h after admission are independently associated with in-hospital mortality in ICU patients. Future research should study whether this association is causal or merely a reflection of differences in severity of illness insufficiently corrected for in the multivariate analysis.
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Affiliation(s)
- Evert de Jonge
- Department of Intensive Care, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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D'Agostino DP, Colomb DG, Dean JB. Effects of hyperbaric gases on membrane nanostructure and function in neurons. J Appl Physiol (1985) 2008; 106:996-1003. [PMID: 18818382 DOI: 10.1152/japplphysiol.91070.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
This mini-review summarizes current ideas of how hyperbaric gases (>1-10 atmospheres absolute) affect neuronal mechanisms of excitability through molecular interaction with membrane components. The dynamic nature of the lipid bilayer, its resident proteins, and the underlying cytoskeleton make each respective nanostructure a potential target for modulation by hyperbaric gases. Depending on the composition of the gas mixture, the relative concentrations of O(2) and inert gas, and total barometric pressure, the net effect of a particular gas on the cell membrane will be determined by the gas' 1) lipid solubility, 2) ability to oxidize lipids and proteins (O(2)), and 3) capacity, in the compressed state, to generate localized shear and strain forces between various nanostructures. A change in the properties of any one membrane component is anticipated to change conductance of membrane-spanning ion channels and thus neuronal function.
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Affiliation(s)
- Dominic P D'Agostino
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, College of Medicine, University of South Florida, Tampa 33612, USA
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