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Thread: CNS discussion (split from the infamous AM thread)

  1. #11
    Old, maybe one day wise Tino de Rijk has a reputation beyond repute Tino de Rijk has a reputation beyond repute Tino de Rijk has a reputation beyond repute Tino de Rijk has a reputation beyond repute Tino de Rijk has a reputation beyond repute Tino de Rijk has a reputation beyond repute Tino de Rijk has a reputation beyond repute Tino de Rijk has a reputation beyond repute Tino de Rijk has a reputation beyond repute Tino de Rijk has a reputation beyond repute Tino de Rijk has a reputation beyond repute Tino de Rijk's Avatar
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    Re: CNS exposure and RB deaths in list

    Quote Originally Posted by MatV  View Original Post
    Hi Tino,


    There is. Some of it is not yet published. There were several doctorate thesis involved in this study group.
    Amongs else, they found a way of detecting oxygen stress in divers and non divers ( athletes), e.g. stress from exposure to high levels of oxygen,, high ambient pressure, exertion, combination thereof, by testing urine samples with expensive machinery, which looked like chromatographic equipment to me.

    I tried to link Andreas to JJ, to speak at the GUE World conference in Budapest last winter, but maybe his expertise is to special for the general GUE set of themes. At least they are aware that we've already got electric lighting in Europe

    Rob Bakker in Norway is working on the same subject, he found ways to detect oxygen stress by blood sampling.

    I understood most of this will be published in full in medical Journals, not in Dive Mags.
    On some subjects, peer review is still going on.

    Cheers,
    Matthias
    Matthias,

    Thanks. Please keep me posted as to progress in making that info publicly available.
    Peer reviews should indeed be in medical magazines. The level of expertise on that subject in dive magazines is, uhm...., "underwhelming".

    As to pigs: well.... looking at my belly, I guess the pig comes closest to mankind. Just my thought ;).. Maybe the pig is even smarter....? At least it admits it likes dirt....

    ciao,

    Tino.

  2. #12
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    Re: CNS exposure and RB deaths in list

    Quote Originally Posted by MatV  View Original Post
    To answer any further questions ( rather to make them rise , here is a link to the presentation, held at a Bonn Symposium. Hope you understand some german, though Bubblefish would probably an interiesting reading...

    Salve,
    Matthias
    Hi Mat

    Could you please post that link again, I seem to be having difficulty finding it.

    Regards

    AnneMarie

  3. #13
    RBW Member MatV is a jewel in the rough MatV is a jewel in the rough MatV is a jewel in the rough MatV is a jewel in the rough MatV is a jewel in the rough MatV is a jewel in the rough MatV is a jewel in the rough MatV's Avatar
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    Re: CNS exposure and RB deaths in list

    Quote Originally Posted by AM  View Original Post
    Hi Mat

    Could you please post that link again, I seem to be having difficulty finding it.

    Regards

    AnneMarie

    Hi Annemarie,
    go to

    Bonner Tauchersymposium

    then to the frame on the left, click downloads, then under 8. Bonner Symposium at the article in question. ( CNS.. etc. Andreas Koch)

    Let me give a brief summary:
    Divers show individual susceptility towards oygen's toxic influence on CNS, varying according to workload, depth, ppO2, individaul factors.
    The bodily protective measures seems, among else, to be composed of the chemical reaction of NO- radicals with Oxygen, leading to reduced blood flow in some vessels (vasoconstruction).
    The "raw materials" sponsoring this reaction seem to get depleted with time, and a.m. factors, and this seems to be the earliest gpossible chance to monitor the beginning of the onset of symptoms, e.g. a switch from reduced blood flow to a higher one.
    To detect this, the cerebral bloodflow had been measured. Results were signifcant, and with this knowledge, and instrumentation, it was possible to stop toxing by reducing ppO2 ( switch to ...)

    (My personal comment: Since we know elevated levels of CO2 will increase cerebral bloodflow....)

    It seems possible to alter the response to oxygen by medication ( vitamin and other) ( MV: from my memory MAO/-Inhibitors may play a role).

    That's what it is in short, and a little bit more, haven't yet recompiled my scripts from the Heidelberg Symposium.

    Greets,
    Matthias

    PS: How's the weather in Egypt right now?

  4. #14
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    Re: CNS exposure and RB deaths in list

    Mat

    Thank you for posting the link, very interesting information but translation is very slow!

    There is a medical symposium soon in London, are you going?

    A question, if I may. The potential to alter the response to oxygen using MAO inhibitors - could you please elaborate on the actual mechanism by which MAOIs might change the response to oxygen?

    Many regards

    AnneMarie

    Quote Originally Posted by MatV  View Original Post
    Hi Annemarie,
    go to

    Bonner Tauchersymposium

    then to the frame on the left, click downloads, then under 8. Bonner Symposium at the article in question. ( CNS.. etc. Andreas Koch)

    Let me give a brief summary:
    Divers show individual susceptility towards oygen's toxic influence on CNS, varying according to workload, depth, ppO2, individaul factors.
    The bodily protective measures seems, among else, to be composed of the chemical reaction of NO- radicals with Oxygen, leading to reduced blood flow in some vessels (vasoconstruction).
    The "raw materials" sponsoring this reaction seem to get depleted with time, and a.m. factors, and this seems to be the earliest gpossible chance to monitor the beginning of the onset of symptoms, e.g. a switch from reduced blood flow to a higher one.
    To detect this, the cerebral bloodflow had been measured. Results were signifcant, and with this knowledge, and instrumentation, it was possible to stop toxing by reducing ppO2 ( switch to ...)

    (My personal comment: Since we know elevated levels of CO2 will increase cerebral bloodflow....)

    It seems possible to alter the response to oxygen by medication ( vitamin and other) ( MV: from my memory MAO/-Inhibitors may play a role).

    That's what it is in short, and a little bit more, haven't yet recompiled my scripts from the Heidelberg Symposium.

    Greets,
    Matthias

    PS: How's the weather in Egypt right now?

  5. #15
    New Member Simon Mitchell has a reputation beyond repute Simon Mitchell has a reputation beyond repute Simon Mitchell has a reputation beyond repute Simon Mitchell has a reputation beyond repute Simon Mitchell has a reputation beyond repute Simon Mitchell has a reputation beyond repute Simon Mitchell has a reputation beyond repute Simon Mitchell has a reputation beyond repute Simon Mitchell has a reputation beyond repute Simon Mitchell has a reputation beyond repute Simon Mitchell has a reputation beyond repute Simon Mitchell's Avatar
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    Re: CNS exposure and RB deaths in list

    Quote Originally Posted by AM  View Original Post
    Mat

    A question, if I may. The potential to alter the response to oxygen using MAO inhibitors - could you please elaborate on the actual mechanism by which MAOIs might change the response to oxygen?

    Many regards

    AnneMarie
    Hello,

    The Koch study has been published in the European Journal of Neurology. The abstract can be found by following the link:

    Monitoring of CBFV and time characteristics of oxy...[Eur J Neurol. 2008] - PubMed Result

    The finding of changes in cerebral blood flow velocity is not new, and was also reported by Visser et al. Their abstract can be found at this link:

    Transcranial Doppler sonographic measurements of m...[Undersea Hyperb Med. 1996] - PubMed Result

    The Koch study corroborates the original Visser finding. However, the practical significance of this finding is unclear. Monitoring cerebral blood flow velocity as a marker for impending seizures would obviously be impractical.

    As for monoamine oxidase inhibitors.... I'm sure you know how they work.... but I'm not sure anyone knows exactly how they might modulate the risk of oxygen toxicity (either up or down). But given their side effect profile I seriously doubt whether anyone would want to take them as prophylaxis against oxygen toxicity in diving.

    Warm regards,

    Simon M

  6. #16
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    Re: CNS exposure and RB deaths in list

    Simon

    I appreciate you taking the time to provide that information.

    It is interesting that Koch and Visser both align on the finding regarding cerebral blood flow alterations.

    Cerebral blood flow velocity monitoring, as you state, is currently not feasible from a practical perspective.

    The potential of the MAOIs to alter the risk of oxygen toxicity by an as yet not fully understood mechanism is interesting although I agree, not practical as a real world mitigation. However, is there any documented information that demonstrates the effects and mechanism of MAOIs on cerebral blood flow velocity?

    Regards

    AnneMarie

    Quote Originally Posted by Simon Mitchell  View Original Post
    Hello,

    The Koch study has been published in the European Journal of Neurology. The abstract can be found by following the link:

    Monitoring of CBFV and time characteristics of oxy...[Eur J Neurol. 2008] - PubMed Result

    The finding of changes in cerebral blood flow velocity is not new, and was also reported by Visser et al. Their abstract can be found at this link:

    Transcranial Doppler sonographic measurements of m...[Undersea Hyperb Med. 1996] - PubMed Result

    The Koch study corroborates the original Visser finding. However, the practical significance of this finding is unclear. Monitoring cerebral blood flow velocity as a marker for impending seizures would obviously be impractical.

    As for monoamine oxidase inhibitors.... I'm sure you know how they work.... but I'm not sure anyone knows exactly how they might modulate the risk of oxygen toxicity (either up or down). But given their side effect profile I seriously doubt whether anyone would want to take them as prophylaxis against oxygen toxicity in diving.

    Warm regards,

    Simon M
    Last edited by AM; 20th October 2008 at 00:58.

  7. #17
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    Re: CNS discussion (split from the infamous AM thread)

    Quote Originally Posted by MatV  View Original Post
    2) You put far too much in the absolute number the familiar CNS algorhythm give, with respect to currently used warning treshold, whereas Alex focus clearly lies on the steep slope of sliding into danger of Oxtox when experiencing higher levels of CO2, whatever the "CNS-value"may be.
    Again this dependancy seems to me quite well known, from the olden days when even Narcosis was attributed to higher CO2 levels, up to the recent publications and studies done at the Kiel Institute by Dr. Andreas Koch and his colloegues.
    He represented his results at the G.T.UE.M.'s scientific meeting in Heidelberg this spring, where he also presenting the time/pp dependancy of the onset of Oxtox symptoms as well as the new found method of detecting in good time to be able to counteract.
    Cheers,
    Matthias
    Mat

    The results presented in Heidelberg, when are these expected to be fully written up?

    Could you please provide further detail on the reference made to the new found method of detecting OxTox symptoms in good time to be able to counteract.

    Many regards

    AnneMarie

  8. #18
    RBW Member MatV is a jewel in the rough MatV is a jewel in the rough MatV is a jewel in the rough MatV is a jewel in the rough MatV is a jewel in the rough MatV is a jewel in the rough MatV is a jewel in the rough MatV's Avatar
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    Re: CNS discussion (split from the infamous AM thread)

    Quote Originally Posted by AM  View Original Post
    Mat

    The results presented in Heidelberg, when are these expected to be fully written up?

    Could you please provide further detail on the reference made to the new found method of detecting OxTox symptoms in good time to be able to counteract.

    Many regards

    AnneMarie
    Hi Annemarie,

    regarding the MAO stuff, listen to Simon...
    As to their effects on the body, many studies have been maade in the realm of psychiatry. (look for n-cyclic antidepressants).

    As to a working method, or a possibility to bring blood flow measurements closer to the diver, therehas yet to be established a method for in water transcranial dopplering. May be Hard Hatters will be the first to have this possibility.
    However, for chamber rides there should be no obvious obstacle, other than cost.

    As for me doing my post-symposium chores, don't expect anything from me in the near future.
    Autumn is coming, and my house is really needing some deal of TLC.

    In the meantime, just follow the link Simon gave.

    greets

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