Acclimatization to decompression

[kbuschmann]

"However, the reference they listed in their paper is from EUBS proceedings:

Bye A, Medbye C, Brubakk AO. Heat shock treatment prior to dive increases survival in rats. In: Grandjean B, Meliet J-L, eds. Proceedings of the 30th annual scientific meeting of the EUBS. Ajaccio, France: EUBS; 2004:208."

EUBS and SPUMS have joined journalistic forces and now publish concurrently in 'Diving and Hyperbaric Medicine'. The study I mentioned is an update/continuation of the one you quote from the earlier EUBS Proceedings.


"..BTW, Peter Z says "Hi"!"

Tell Peter he's beautiful.

 

[Dawn_Kernagis]

"However, the reference they listed in their paper is from EUBS proceedings:

Bye A, Medbye C, Brubakk AO. Heat shock treatment prior to dive increases survival in rats. In: Grandjean B, Meliet J-L, eds. Proceedings of the 30th annual scientific meeting of the EUBS. Ajaccio, France: EUBS; 2004:208."

EUBS and SPUMS have joined journalistic forces and now publish concurrently in 'Diving and Hyperbaric Medicine'. The study I mentioned is an update/continuation of the one you quote from the earlier EUBS Proceedings.


"..BTW, Peter Z says "Hi"!"

Tell Peter he's beautiful.

Yes, sorry I didn't point out the journal affiliations and clarify the difference between the two papers in my previous post...more of a comment that the study was briefly mentioned in the discussion, but definitely not meant as a correction to your post!

If anyone wants to take a look at the study, the current reference Kim posted is a bit more thorough and updated with follow-up data. My guess is that paper would also be easier to track down than something from the 2004 conference proceedings.

Kim, Peter says we are all beautiful people. Ricardo says you need glasses.

Have a great day!
Dawn

 

[Dr Deco]

Hello Readers :

Rats

Many have written to indicate recent research on biochemical mechanism of DCS. I caution readers to note that much of this work [though not all] has been performed using rats as test subjects. The endpoint in these rat studies is paraplegia or death.. The endpoint in human diving is not death this is not the joint pain DCS that we typically encounter as recreational divers. Dick Vann recently co-wrote a paper on endpoints and the identification of DCS in human experiments. Death was never mention.Many of the "rodent runners" will admit that rats do not get the "bends," but mild DCS of that type is not interesting to them, anyway. [I know this from many discussions with Bruce Butler and Alf Brubakk.]

Animals do not get joint-pain DCS in the same way that humans do - especially rats This was mention by JS Haldane in his landmark paper of 1908. [Many today should read it. Gene Hobbs has a copy on his site.]

Doppler Bubbles

In some of these papers, the authors reference the relationship of vascular (Doppler) bubbles to DCS. This is NOT cause and effect, and this has been known for more than thirty years. I published the first papers on this non-relationship in the early 1970s!

Cavitation Tendency

It is known that cavitation tendency (bubble formation) differs amongst individuals. I wanted to study this at NASA, but time and money ran out, and I retired. If DCS is the result of a free gas phase, why do some form it more readily than others do?

This is the question.

Dr Deco :doctor:

 

[Dawn_Kernagis]

Dr. Powell,

Well said, thank you for the excellent post. Several points you made which I completely agree with:

1)Although I agree there is a tremendous amount of benefit to using animal models (with the ability to gather tissue samples, minimize conditional effects (exercise, diet, etc), use genetically modified strains to single out particular phenotypes, etc), there are also things to keep in mind with animal studies. As you pointed out, some (not all) of the animal decompression models include explosive profiles...as one of my mentors stated in a rather tongue-in-cheek way, you could throw the animal against the wall and get similar effects (sorry for the image). This does not mimic a typical human decompression profile that would induce DCS.

Some of the studies mentioned earlier in this thread did use humans, but the tricky thing with humans studies is minimizing the 'outside' variables. Openwater diving subjects means varied profiles, exercise loads, pre and post dive effects, etc. Chamber diving human subjects minimizes some of these variables, but still not perfect. Regardless, the direct model applicability of these studies is obvious over animal models. Then again, with humans there is a 'limitation' to what kind of data we can collect...Doppler, TTE, TCD, blood samples and other fluid collection, muscle biopsy, BP, HR, pulseox, etc...however, we can also get creative with the current technology on hand and pull together some very interesting data/information from human studies.

I guess there are cautions that should be thrown out with all papers/references in a suggested reading list, regardless of what the topic may be. We have a Pathology journal club that spends two days a week critically discussing molecular biology papers (as do most research and clinical departments) - what is good science, what is not so good science, how it could be better, and how does it really, truly applies in the big picture...

2) The lack of bubble and DCS correlation - this is definitely an issue that can often be overlooked in papers. As you said, there is individual variability...really on two levels. The first is difference in the formation of gas emboli; the second is a difference in response to the presence of gas emboli. This is actually the main focus of my thesis work here at Duke, so I hope in the next several years we will have a better peak at the why's and how's of individual variability!

Best,
Dawn

Hello Readers :

Rats

Many have written to indicate recent research on biochemical mechanism of DCS. I caution readers to note that much of this work [though not all] has been performed using rats as test subjects. The endpoint in these rat studies is paraplegia or death.. The endpoint in human diving is not death this is not the joint pain DCS that we typically encounter as recreational divers. Dick Vann recently co-wrote a paper on endpoints and the identification of DCS in human experiments. Death was never mention.Many of the "rodent runners" will admit that rats do not get the "bends," but mild DCS of that type is not interesting to them, anyway. [I know this from many discussions with Bruce Butler and Alf Brubakk.]

Animals do not get joint-pain DCS in the same way that humans do - especially rats This was mention by JS Haldane in his landmark paper of 1908. [Many today should read it. Gene Hobbs has a copy on his site.]

Doppler Bubbles

In some of these papers, the authors reference the relationship of vascular (Doppler) bubbles to DCS. This is NOT cause and effect, and this has been known for more than thirty years. I published the first papers on this non-relationship in the early 1970s!

Cavitation Tendency

It is known that cavitation tendency (bubble formation) differs amongst individuals. I wanted to study this at NASA, but time and money ran out, and I retired. If DCS is the result of a free gas phase, why do some form it more readily than others do?

This is the question.

Dr Deco :doctor:

 

[scubadada]

As a physician, and animal researcher in a previous life, the caveats on generalizing from animal studies are not lost on me. This thread has turned out to be very lively and informative. I'm very appreciative for the participation by my knowledgeable colleagues, thanks.

Good diving, Craig