Mechanisms Of Metabolic Coronary Flow Regulation
Adenosine; arteriolar; Carbon dioxide; Cardiovascular System & Cardiology; Cell Biology; Coronary blood flow; dilation; guinea-pig heart; heterogeneity; hydrogen-peroxide; hypercapnic acidosis; Ion channels; k-atp channels; microvascular dilation; myocardial blood-flow; nitric-oxide; nitric-oxide; Oxygen; Prostaglandins; Reactive oxygen species; sensitive potassium channels; spatial
Deussen A; Ohanyan V; Jannasch A; Yin L Y; Chilian W
Journal of Molecular and Cellular Cardiology
2012
2012-04
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1016/j.yjmcc.2011.10.001" target="_blank" rel="noreferrer noopener">10.1016/j.yjmcc.2011.10.001</a>
Systemic consequences of oxidative stress following aortic surgery correlate with the degree of antioxidant defenses
Surgery; oxygen; pulmonary-edema; Cardiovascular System & Cardiology; capacity; ischemia-reperfusion injury; radicals; lung injury; depletion; mediators; xanthine-oxidase
The purpose of this study was to correlate the preoperative level of antioxidant defenses, measured by the plasma total antioxidant capacity (TAC), to the degree of postoperative systemic inflammatory response, measured by the severity of pulmonary injury following elective aortic surgery. Twenty-four patients had TAC measured preoperatively and 24 hr postoperatively. Chest radiography and arterial blood gases were obtained preoperatively and serially during the first 24 hr after surgery. Using objective radiologic criteria and blood gas analysis, the degree of pulmonary edema and pulmonary dysfunction were quantified. All patients showed evidence of pulmonary dysfunction in the first 24 hr following surgery. Fifteen of the 24 patients showed radiographic evidence of noncardiogenic pulmonary edema in the immediate postoperative period. In this group, the TAC was lower than in those without pulmonary edema immediately following surgery (p = 0.03). Preoperative TAC was associated with the degree of pulmonary edema in the postoperative period (r = -0.372, p = 0.067). These results suggest that preoperative antioxidant supplementation may favorably impact the severity of systemic inflammatory response following ischemia and reperfusion injury. DOI: 10.1007/s100169910006.
Cornu-Labat G; Serra M; Smith A; McGregor W E; Kasirajan K; Hirko M K; Turner J J; Rubin J R
Annals of Vascular Surgery
2000
2000-01
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1007/s100169910006" target="_blank" rel="noreferrer noopener">10.1007/s100169910006</a>
Excess no predisposes mitochondrial succinate-cytochrome c reductase to produce hydroxyl radical
Mitochondria; Biophysics; oxygen; Biochemistry & Molecular Biology; nitric-oxide synthase; reactive; smooth-muscle-cells; endothelial-cells; reperfusion injury; EPR; postischemic heart; complex-ii; Electron transport chain; electron-transport; Hydroxyl radical; NO; oxygen-free radicals; SCR; spin trapping; superoxide generation
Mitochondria-derived oxygen-free radical(s) are important mediators of oxidative cellular injury. It is widely hypothesized that excess NO enhances O(2)(center dot-) generated by mitochondria under certain pathological conditions. In the mitochondrial electron transport chain, succinate-cytochrome c reductase (SCR) catalyzes the electron transfer reaction from succinate to cytochrome c. To gain the insights into the molecular mechanism of how NO overproduction may mediate the oxygen-free radical generation by SCR, we employed isolated SCR, cardiac myoblast H9c2, and endothelial cells to study the interaction of NO with SCR in vitro and ex vivo. Under the conditions of enzyme turnover in the presence of NO donor (DEANO), SCR gained pro-oxidant function for generating hydroxyl radical as detected by EPR spin trapping using DEPMPO. The EPR signal associated with DEPMPO/(center dot)OH adduct was nearly completely abolished in the presence of catalase or an iron chelator and partially inhibited by SOD, suggesting the involvement of the iron-H(2)O(2)-dependent Fenton reaction or O(2)(center dot-)-dependent Haber-Weiss mechanism. Direct EPR measurement of SCR at 77 K indicated the formation of a nonheme iron-NO complex, implying that electron leakage to molecular oxygen was enhanced at the FAD cofactor, and that excess NO predisposed SCR to produce (center dot)OH. In H9c2 cells, SCR-dependent oxygen-free radical generation was stimulated by NO released from DEANO or produced by the cells following exposure to hypoxia/reoxygenation. With shear exposure that led to overproduction of NO by the endothelium, SCR-mediated oxygen-free radical production was also detected in cultured vascular endothelial cells. (C) 2011 Elsevier B.V. All rights reserved.
Chen J F; Chen C L; Alevriadou B R; Zweier J L; Chen Y R
Biochimica Et Biophysica Acta-Bioenergetics
2011
2011-05
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1016/j.bbabio.2011.03.001" target="_blank" rel="noreferrer noopener">10.1016/j.bbabio.2011.03.001</a>
Metabolic consequences of behavioural hypothermia and oxygen detection in submerged overwintering frogs
hypoxia; exercise; oxygen; recovery; Zoology; temperature; amphibians; rana-catesbeiana; bullfrogs; metabolic fuels; metabolic suppression; muscosa; temperature gradients
The common frog, Rana temporaria, overwinters under the ice of frozen lakes and ponds, during which time metabolic, respiratory and behavioural adjustments act in concert to conserve metabolic fuels by promoting aerobic metabolism. Animal behaviour under the ice is poorly understood, but given that spatial and temporal gradients for temperature and oxygen develop throughout the winter, behavioural thermoregulation may allow the selection of aerobic microenvironments that are conducive to overwintering survival. Accordingly, we have examined the thermoregulatory behaviour and metabolism of cold-submerged frogs in an experimental 'gradient chamber' designed to mimic overwintering conditions in nature. The preferred temperature of 7 degrees C in normoxia decreases to 1.5 degrees C in severe hypoxia, and coincides: with an aerobic metabolic saving of 70-85% and a delay in the onset of a runaway lactacidosis. Following intense exercise, temperature preferences are also lowered from 6.7 degrees C to 3.6 degrees C for upwards of 7 hours in a fashion reminiscent of the 'behavioural hypothermia' response to hypoxia. Cold-submerged frogs are also able to detect isothermal variations in dissolved oxygen and spend 70% of their time at oxygen partial pressures that promote aerobic metabolism. The ability to exploit gradients of oxygen and temperature has strong ecological relevance to over-wintering since the behavioural selection of preferred microhabitats is consistent with minimising the metabolic stresses associated with either hypoxia or hypothermia and promoting survival.
Boutilier R G; Tattersall G J; Donohoe P H
Zoology-Analysis of Complex Systems
2000
2000
Journal Article or Conference Abstract Publication
n/a
Adaptations for marine habitat and the effect of Triassic and Jurassic predator pressure on development of decompression syndrome in ichthyosaurs
body; Caisson disease; deep; endothermy; evolution; Ichthyosaurs; oxygen; red muscle; reptiles; Science & Technology - Other Topics; swimming speed; thunnus-thynnus; Triassic; tuna katsuwonus-pelamis
Decompression syndrome (caisson disease or the "the bends") resulting in avascular necrosis has been documented in mosasaurs, sauropterygians, ichthyosaurs, and turtles from the Middle Jurassic to Late Cretaceous, but it was unclear that this disease occurred as far back as the Triassic. We have examined a large Triassic sample of ichthyosaurs and compared it with an equally large post-Triassic sample. Avascular necrosis was observed in over 15 % of Late Middle Jurassic to Cretaceous ichthyosaurs with the highest occurrence (18 %) in the Early Cretaceous, but was rare or absent in geologically older specimens. Triassic reptiles that dive were either physiologically protected, or rapid changes of their position in the water column rare and insignificant enough to prevent being recorded in the skeleton. Emergency surfacing due to a threat from an underwater predator may be the most important cause of avascular necrosis for air-breathing divers, with relative frequency of such events documented in the skeleton. Diving in the Triassic appears to have been a "leisurely" behavior until the evolution of large predators in the Late Jurassic that forced sudden depth alterations contributed to a higher occurrence of bends.
Rothschild B M; Xiaoting Z; Martin L D
Naturwissenschaften
2012
2012-06
Journal Article
<a href="http://doi.org/10.1007/s00114-012-0918-0" target="_blank" rel="noreferrer noopener">10.1007/s00114-012-0918-0</a>