Myocardial stunning - we do not know the mechanism nor is there "overwhelming evidence" for a major role of free radicals

1998 ◽  
Vol 93 (3) ◽  
pp. 152-155 ◽  
Author(s):  
L.H. Opie
Keyword(s):  
Free Radicals ◽  
Myocardial Stunning ◽  
Overwhelming Evidence

Evidence for a pathogenetic role of xanthine oxidase in the "stunned" myocardium

1987 ◽  
Vol 252 (3) ◽  
pp. H566-H577 ◽  
Author(s):  
M. I. Charlat ◽  
P. G. O'Neill ◽  
J. M. Egan ◽  
D. R. Abernethy ◽  
L. H. Michael ◽  
...  
Keyword(s):  
Free Radicals ◽  
Xanthine Oxidase ◽  
Myocardial Stunning ◽  
Oxygen Free Radicals ◽  
Contractile Function ◽  
Myocardial Dysfunction ◽  
Stunned Myocardium ◽  
Base Line ◽  
Collateral Flow

Recent evidence suggests that postischemic myocardial dysfunction (or myocardial “stunning”) may be mediated by oxygen free radicals, but the mechanism for their production remains unknown. To explore the role of xanthine oxidase as a potential source of free radicals, open-chest dogs undergoing a 15-min occlusion of the left anterior descending coronary artery (LAD) followed by 4 h of reperfusion (REP) received intravenously either allopurinol (50 mg/kg 48 h, 20 h, and 30 min before occlusion, 10 mg/kg 1 min before REP, and 6.25 mg X kg-1 X h-1 throughout REP, n = 13) or saline (n = 14). The two groups were similar with respect to occluded bed size (postmortem perfusion) and collateral flow (radioactive microspheres). In controls, the transcardiac difference in plasma uric acid (great cardiac vein - arterial concentration) increased 199 +/- 70% (means +/- SE) during ischemia (P less than 0.02) and remained elevated for 5 min after REP; no increase was observed in treated dogs. Regional myocardial function was assessed by measuring systolic wall thickening with an epicardial Doppler probe. The two groups exhibited comparable systolic thickening under base-line conditions and similar degrees of dyskinesis during ischemia. Following REP, however, recovery of contractile function (expressed as percent of preocclusion values) was considerably greater in allopurinol-treated as compared with control dogs: 57 +/- 14 vs. -22 +/- 16 (P less than 0.01) at 1 h, 70 +/- 13 vs. -15 +/- 15 (P less than 0.001) at 2 h, 65 +/- 14 vs. -28 +/- 13 (P less than 0.001) at 3 h, and 68 +/- 13 vs. -17 +/- 14 (P less than 0.001) at 4 h. These differences could not be ascribed to hemodynamic factors. The results suggest that xanthine oxidase is a source of the oxygen free radicals responsible for myocardial stunning following a brief episode of reversible regional ischemia.

The Role of free radicals in female unexplained subfertility

2020 ◽  
Vol 23 (01) ◽  
pp. 01-08
Author(s):  
Ban Jaber Edan ◽  
Huda Mahmood Shakir ◽  
Naseer Jwaad Almukhtar
Keyword(s):  
Free Radicals

Study of antioxidant potential in leaves, stems, nuts of Juglans regia L.

2012 ◽  
Vol 1 (10) ◽  
pp. 79 ◽  
Author(s):  
G. Raja* ◽  
Ivvala Anand Shaker ◽  
Inampudi Sailaja ◽  
R. Swaminathan ◽  
S. Saleem Basha ◽  
...  
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Juglans Regia ◽  
Radical Scavenging ◽  
Antioxidant Compounds ◽  
Free Radical Damage ◽  
Radical Damage

Natural antioxidants can protect the human body from free radicals and retard the progress of many chronic diseases as well as lipid oxidative rancidity in foods. The role of antioxidants has protected effect against free radical damage that may cause many diseases including cancer. Primary sources of naturally occurring antioxidants are known as whole grains, fruits, and vegetables. Several studies suggest that regular consumption of nuts, mostly walnuts, may have beneficial effects against oxidative stress mediated diseases such as cardiovascular disease and cancer. The role of antioxidants has attracted much interest with respect to their protective effect against free radical damage that may cause many diseases including cancer. Juglans regia L. (walnut) contains antioxidant compounds, which are thought to contribute to their biological properties. Polyphenols, flavonoids and flavonols concentrations and antioxidant activity of Leaves, Stems and Nuts extract of Juglans regia L. as evaluated using DPPH, ABTS, Nitric acid, hydroxyl and superoxide radical scavenging activity, lipid peroxidation and total oxidation activity were determined. The antioxidant activities of Leaves, Stems and Nuts extract of Juglans regia L. were concentration dependent in different experimental models and it was observed that free radicals were scavenged by the test compounds in all the models.

scholarly journals Oxidized LDLs as Signaling Molecules

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1184
Author(s):  
Jean-Marc Zingg ◽  
Adelina Vlad ◽  
Roberta Ricciarelli
Keyword(s):  
Free Radicals ◽  
Cellular Response ◽  
Vascular System ◽  
Signaling Molecules ◽  
Scavenger Receptors ◽  
Physiological Relevance ◽  
Reactive Radicals ◽  
Accumulation Of Lipids

Levels of oxidized low-density lipoproteins (oxLDLs) are usually low in vivo but can increase whenever the balance between formation and scavenging of free radicals is impaired. Under normal conditions, uptake and degradation represent the physiological cellular response to oxLDL exposure. The uptake of oxLDLs is mediated by cell surface scavenger receptors that may also act as signaling molecules. Under conditions of atherosclerosis, monocytes/macrophages and vascular smooth muscle cells highly exposed to oxLDLs tend to convert to foam cells due to the intracellular accumulation of lipids. Moreover, the atherogenic process is accelerated by the increased expression of the scavenger receptors CD36, SR-BI, LOX-1, and SRA in response to high levels of oxLDL and oxidized lipids. In some respects, the effects of oxLDLs, involving cell proliferation, inflammation, apoptosis, adhesion, migration, senescence, and gene expression, can be seen as an adaptive response to the rise of free radicals in the vascular system. Unlike highly reactive radicals, circulating oxLDLs may signal to cells at more distant sites and possibly trigger a systemic antioxidant defense, thus elevating the role of oxLDLs to that of signaling molecules with physiological relevance.

scholarly journals Environmentally persistent free radicals are ubiquitous in wildfire charcoals and remain stable for years

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Gabriel Sigmund ◽  
Cristina Santín ◽  
Marc Pignitter ◽  
Nathalie Tepe ◽  
Stefan H. Doerr ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Reactive Oxygen ◽  
Resonance Spectroscopy ◽  
Oxygen Species ◽  
Pyrogenic Carbon ◽  
Spin Resonance ◽  
Long Time ◽  
High Concentrations

AbstractGlobally landscape fires produce about 256 Tg of pyrogenic carbon or charcoal each year. The role of charcoal as a source of environmentally persistent free radicals, which are precursors of potentially harmful reactive oxygen species, is poorly constrained. Here, we analyse 60 charcoal samples collected from 10 wildfires, that include crown as well as surface fires in forest, shrubland and grassland spanning different boreal, temperate, subtropical and tropical climate. Using electron spin resonance spectroscopy, we measure high concentrations of environmentally persistent free radicals in charcoal samples, much higher than those found in soils. Concentrations increased with degree of carbonization and woody fuels favoured higher concentrations. Moreover, environmentally persistent free radicals remained stable for an unexpectedly long time of at least 5 years. We suggest that wildfire charcoal is an important global source of environmentally persistent free radicals, and therefore potentially of harmful reactive oxygen species.

scholarly journals Inevitable future: space colonization beyond Earth with microbes first

2019 ◽  
Vol 95 (10) ◽  
Author(s):  
Jose V Lopez ◽  
Raquel S Peixoto ◽  
Alexandre S Rosado
Keyword(s):  
Potential Space ◽  
Public And Private ◽  
Planetary Protection ◽  
Overwhelming Evidence ◽  
Future Space ◽  
Private Research ◽  
Life On Earth ◽  
Space Colonization ◽  
Future Plans

ABSTRACT Based on modern microbiology, we propose a major revision in current space exploration philosophy and planetary protection policy, especially regarding microorganisms in space. Mainly, microbial introduction should not be considered accidental but inevitable. We hypothesize the near impossibility of exploring new planets without carrying and/or delivering any microbial travelers. In addition, although we highlight the importance of controlling and tracking such contaminations—to explore the existence of extraterrestrial microorganisms—we also believe that we must discuss the role of microbes as primary colonists and assets, rather than serendipitous accidents, for future plans of extraterrestrial colonization. This paradigm shift stems partly from the overwhelming evidence of microorganisms’ diverse roles in sustaining life on Earth, such as symbioses and ecosystem services (decomposition, atmosphere effects, nitrogen fixation, etc.). Therefore, we propose a framework for new discussion based on the scientific implications of future colonization and terraforming: (i) focus on methods to track and avoid accidental delivery of Earth's harmful microorganisms and genes to extraterrestrial areas; (ii) begin a rigorous program to develop and explore ‘Proactive Inoculation Protocols’. We outline a rationale and solicit feedback to drive a public and private research agenda that optimizes diverse organisms for potential space colonization.

The role of free radicals in cold injuries

1995 ◽  
Vol 38 (4) ◽  
pp. 171-175 ◽  
Author(s):  
G. Bhaumik ◽  
K. K. Srivastava ◽  
W. Selvamurthy ◽  
S. S. Purkayastha
Keyword(s):  
Free Radicals

Role of Free Radicals and Lipid Peroxidation in Gastric Mucosal Injury Induced by Ischemia-Reperfusion in Rats

1989 ◽  
Vol 24 (sup162) ◽  
pp. 55-58 ◽  
Author(s):  
S. Ueda ◽  
T. Yoshikawa ◽  
S. Takahashi ◽  
H. Ichikawa ◽  
M. Yasuda ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Free Radicals ◽  
Ischemia Reperfusion ◽  
Mucosal Injury ◽  
Gastric Mucosal Injury

Strand scission in DNA induced by dietary flavonoids: role of Cu(I) and oxygen free radicals and biological consequences of scission

1992 ◽  
Vol 111 (1-2) ◽  
Author(s):  
Arshad Rahman ◽  
Fabeha Fazal ◽  
Julie Greensill ◽  
K. Ainley ◽  
J.H. Parish ◽  
...  
Keyword(s):  
Free Radicals ◽  
Oxygen Free Radicals ◽  
Strand Scission ◽  
Dietary Flavonoids

Degradation ofp-Nitrophenol on Biochars: Role of Persistent Free Radicals

2015 ◽  
Vol 50 (2) ◽  
pp. 694-700 ◽  
Author(s):  
Jing Yang ◽  
Bo Pan ◽  
Hao Li ◽  
Shaohua Liao ◽  
Di Zhang ◽  
...  
Keyword(s):  
Free Radicals
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