title: Skeletal muscle and glioma oxygenation by carbogen inhalation in rats: a longitudinal study by EPR oximetry using single-probe implantable oxygen sensors.
abstract: The feasibility of EPR oximetry using a single-probe implantable oxygen sensor (ImOS) was tested for repeated measurement of pO₂ in skeletal muscle and ectopic 9L tumors in rats. The ImOS (50 mm length) were constructed using nickel-chromium alloy wires, with lithium phthalocyanine (LiPc, oximetry probe) crystals loaded in the sensor loop and coated with AF 2400(®) Teflon. These ImOS were implanted into the skeletal muscle in the thigh and subcutaneous 9L tumors. Dynamic changes in tissue pO₂ were assessed by EPR oximetry at baseline, during tumor growth, and repeated hyperoxygenation with carbogen breathing. The mean skeletal muscle pO₂ of normal rats was stable and significantly increased during carbogen inhalation in experiments repeated for 12 weeks. The 9L tumors were hypoxic with a tissue pO₂ of 12.8 ± 6.4 mmHg on day 1; however, the response to carbogen inhalation varied among the animals. A significant increase in the glioma pO₂ was observed during carbogen inhalation on day 9 and day 14 only. In summary, EPR oximetry with ImOS allowed direct and longitudinal oxygen measurements in deep muscle tissue and tumors. The heterogeneity of 9L tumors in response to carbogen highlights the need to repeatedly monitor pO₂ to confirm tumor oxygenation so that such changes can be taken into account in planning therapies and interpreting results.
authors.affiliation: Department of Radiology, Geisel School of Medicine, Hanover, NH, 03755, USA. Huagang.Hou@Dartmouth.Edu.|Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA. Huagang.Hou@Dartmouth.Edu.|EPR Center for Viable Systems, Department of Radiology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA. Huagang.Hou@Dartmouth.Edu.
authors.forename: Huagang
authors.initials: H
authors.lastname: Hou
authors.affiliation: Department of Radiology, Geisel School of Medicine, Hanover, NH, 03755, USA.|Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA.
authors.forename: Nadeem
authors.initials: N
authors.lastname: Khan
authors.affiliation: Department of Radiology, Geisel School of Medicine, Hanover, NH, 03755, USA.
authors.forename: Jean
authors.initials: J
authors.lastname: Lariviere
authors.affiliation: Department of Surgery, Geisel School of Medicine, Hanover, NH, 03755, USA.
authors.forename: Sassan
authors.initials: S
authors.lastname: Hodge
authors.affiliation: Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA.|Department of Surgery, Geisel School of Medicine, Hanover, NH, 03755, USA.
authors.forename: Eunice Y
authors.initials: EY
authors.lastname: Chen
authors.affiliation: Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA.|Department of Medicine, Geisel School of Medicine, Hanover, NH, 03755, USA.
authors.forename: Lesley A
authors.initials: LA
authors.lastname: Jarvis
authors.affiliation: Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA.|Department of Pharmacology, Geisel School of Medicine, Hanover, NH, 03755, USA.
authors.forename: Alan
authors.initials: A
authors.lastname: Eastman
authors.affiliation: Department of Radiology, Geisel School of Medicine, Hanover, NH, 03755, USA.|Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA.
authors.forename: Benjamin B
authors.initials: BB
authors.lastname: Williams
authors.affiliation: Department of Radiology, Geisel School of Medicine, Hanover, NH, 03755, USA.|Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA.
authors.forename: Periannan
authors.initials: P
authors.lastname: Kuppusamy
authors.affiliation: EPR Center for the Study of Viable Systems, The Geisel School of Medicine at Dartmouth, Lebanon, NH, USA.
authors.forename: Harold M
authors.initials: HM
authors.lastname: Swartz
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D015374:Biosensing Techniques; D001932:Brain Neoplasms / Q000378:metabolism*; D002245:Carbon Dioxide / Q000008:administration & dosage*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005910:Glioma / Q000378:metabolism*; D008137:Longitudinal Studies; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000008:administration & dosage / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D002245:Carbon Dioxide; C011700:carbogen; D010100:Oxygen
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