title: Effect of SF6-O2 (80/20) breathing on air bubbles in rat tissues.
abstract: We studied the effect of SF6-O2 breathing on air bubbles injected into skeletal muscle, rat-tail tendon, the anterior chamber of the eye, and spinal white matter. Decompression-induced nitrogen bubbles in adipose tissue were studied during breathing of SF6-O2 (80/20). The results of SF6-O2 breathing are compared with previous experiments using heliox (80/20) as the breathing medium. Bubbles studied in skeletal muscle, eye chamber, and spinal white matter were found to behave in a two-phased manner during SF6-O2 (80/20) breathing. All bubbles would initially decrease rapidly in size for a period of 10-80 min (depending on the tissue). Subsequently, the bubbles stabilized and decreased in size with a shrinking rate near zero. In spinal white matter, very small bubbles decreased size with a shrinking rate near zero. In spinal white matter, very small bubbles could disappear before development of the slow phase. All bubbles in tendon shrank at a rather constant rate during SF6-O2 (80/20) breathing until they disappeared. During SF6-O2 (80/20) breathing, all bubbles in adipose tissue shrank and disappeared at least as fast as during heliox (80/20) breathing. Just before disappearance of the bubbles the shrinking rate slowed. Comparison of the effects of SF6-O2 (80/20) and heliox (80/20) breathing suggests that countercurrent gas exchange is at work in some tissues.
authors.affiliation: Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark.
authors.forename: O
authors.initials: O
authors.lastname: Hyldegaard
authors.forename: J
authors.initials: J
authors.lastname: Madsen
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D003665:Decompression Sickness / Q000378:metabolism* / Q000628:therapy; D004058:Diffusion; D005260:Female; D018482:Muscle, Skeletal / Q000378:metabolism; D005741:Noble Gases / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D013116:Spinal Cord / Q000378:metabolism; D013459:Sulfur Hexafluoride / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D013710:Tendons / Q000378:metabolism
chemical_list: D005741:Noble Gases; D013459:Sulfur Hexafluoride