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Post by al on Jun 25, 2014 23:36:55 GMT -5
TOXIC FREE RADICAL-- OXYGEN
The most toxic free radical appears responsible for much of the lung damage that can result from oxygen therapy in the critically ill or injured, Medical College of Georgia researchers report.
Within just a few days, ventilators and oxygen chambers used to significantly increase oxygen levels can also dramatically increase levels of peroxynitrite, an oxidant powerful enough to break down DNA and cause proteins to malfunction, said Dr. Yunchao Su, pharmacologist in the MCG Schools of Medicine and Graduate Studies.
Oxygen toxicity is the most severe side effect of oxygen therapy in newborns and adults. The lungs take the brunt of the damage, which can include inflammation, hemorrhaging and swelling that may result in death or chronic lung problems, said Su, corresponding author of the study published in the Journal of Biological Chemistry.
"We knew it was bad but we did not know why," Su said. The good news is they may also have a solution.
Researchers found that within five days, mice placed in small oxygen chambers that mimic oxygen levels given in intensive care have dramatically elevated levels of peroxynitrite in their lungs. Free radicals, such as peroxynitrite, result from oxygen use and are safe at low levels. While it's a given that oxygen therapy produces free radicals, the significant increase in peroxynitrite was not known.
The trouble begins when high oxygen levels prompt endothelial cells that line blood vessels and tiny airs sacs in the lung to make more nitric oxide, the precursor of peroxynitrite. At high levels, nitric oxide, most often a helpful compound, combines with other free radicals produced by excess oxygen use to form the powerful peroxynitrite. "As oxygen levels increase, nitric oxide levels increase and so peroxynitrite levels do as well," Su said.
But he appears to have identified a break point in the destructive cycle. Su found that in the face of high oxygen levels, the enzyme that makes nitric oxide binds with the protein actin to produce more nitric oxide. So he developed a compound, peptide 326, that interferes with their binding and the excess peroxynitrite levels that typically follow. Su used the binding site itself as a cue for the peptide design after trying many existing compounds, including smoke, to break the bond.
Su's long term goal is for peptide 326, or something similar, to be used in patients likely after the first few days of oxygen therapy. Much as health care providers monitor blood oxygen long term to ensure sufficient levels, they could also monitor peroxynitrite levels. "It's only after several days of steady increases that the level becomes destructive," Su noted.
MCG scientists are already using peptide 326 in mice receiving oxygen therapy.
The research was funded by the National Institutes of Health, the American Heart Association and the Flight Attendants Medical Research Institute.
Dr. Dmitry Kondrikov, assistant research scientist at MCG, is first author of the paper; graduate student Shawn Elms and vascular biologist Dr. David Fulton are co-authors.
Story Source:
The above story is based on materials provided by Medical College of Georgia. The original article was written by Toni Baker. Note: Materials may be edited for content and length.
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Post by sandy07 on Jun 26, 2014 22:56:58 GMT -5
Interesting.
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Post by Sue in Ontario on Jul 8, 2014 15:41:56 GMT -5
Thanks Chris,I constantly worry about oxygen,was told I have a life span of 7 yrs by one Dr.and another says nonsence,he has seen 20 yrs and more it is in how well we take care of ourselves,I am finally getting out more and breaking free of the stigma I felt using oxygen,what a good feeling,I am 53 and plan on living a lot more yrs!Thanks for the input!
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Post by shelley on Jul 10, 2014 16:12:23 GMT -5
Sue don't get wrapped up in that. Everyone is different and progresses differently. I was diagnosed when I was 36 and my FEV1 then was only 48%. Time has marched on but I've been very active the last 23 years and still keep on going. I'm in my 8th year of using oxygen. Unlike Chris, I can't get 96% sitting unless I raise my flow over 4 LPM (hurts a little too much to have it there all the time) and I use 8 LPM getting around and exercising but the key part of that is, I'm still getting around and I most surely would not be without oxygen.
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Post by LindaNY on Jul 12, 2014 18:50:34 GMT -5
Do you have a link to the Article?
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Post by David on Jul 12, 2014 19:59:23 GMT -5
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Post by judi on Jul 17, 2014 13:30:35 GMT -5
Oxidation is something everyone has to live with on an oxygen rich planet, its why cut apples brown and iron rusts. The damaging effects of peroxynitrite on health aren't limited to us, it is implicated in things like Alzheimer's. Multiple Sclerosis, etc. I can't figure out from the article if they are only talking about high levels used with ventilators, etc. or oxygen use in general. I imagine its dose dependent, the higher the dose the more oxidative stress. We are probably all getting some from our O2 but the alternative (earlier death) is a lot more damaging. :-D This is one reason we need to eat lots of fruit and vegetables. A free radical is just a 'loose' oxygen molecule that bounces around and causes tissue damage, some compounds tend to bond with that molecule and 'catch' it so it can't do that anymore and we can get those from good food. I apologize for this hard to read link, I couldn't find any that were easily readable and I wanted to show something to prove I didn't just make this up.:-D The compounds they mention are in green tea, citrus, apples, some veggies, red wine, etc. I have read other articles that list other things.. if it grows just eat it. Uric acid from the metabolism of purines in meat was also mentioned, that is also in asparagus, beans, lentils and some other vegetables. I think it takes a lot of veggies (and salmon), etc and some time but it seems to have helped me. judi www.ncbi.nlm.nih.gov/pubmed/16596994 |
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