Since 1997
Micronuclei FAQ
by Neal W. Pollock, Ph.D. on April 10th, 2017

In a recent DAN article about exercise and diving, I read the following:

Intense physical activity — generally with substantial muscular forces and joint loading (the application of forces on joints) — is believed to transiently increase micronuclei activity, the
presumed agent of bubble formation.

Are these micronuclei preexisting? Where do micronuclei come from, and how are they formed or created?
​The source point for bubble formation is one of the great mysteries in diving science. We know that bubbles form at relatively low gas supersaturations, suggesting some biological facilitation of the process, but we do not yet have the imaging tools to see the initial formation. This technology will come, but it's not available yet. Other methods to identify the sites of formation also continue.

Micronuclei may comprise multiple structures. Whatever they are, they are preexisting, and their activity of facilitating bubble formation can be influenced by acute events (most notably recent pressure excursions that act as preconditioning to alter the responsiveness). Altered responsiveness appears to be transient, indicating a dynamic state or ongoing replacement. If you want to see micronuclei in action, look at a glass of beer. You can often see streams of bubbles originating from apparently singular points on the side of the glass. These points are often associated with defects in the glass, effectively small cracks within which micronuclei formation points exist. It is thought that the micronuclei are lodged in the cracks and act to crank out bubble after bubble. Even if this cannot provide all the answers, it can make for a pleasant interlude if you enjoy beer.

Ultimately, we can see bubbles best in the vascular system, and we have a good idea when they develop and what effects they can have. When we are vague on the specifics of the actual formation, it is an honest acknowledgment of understanding yet to come.


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