title: Gloxy: an oxygen-sensitive coal for accurate measurement of low oxygen tensions in biological systems.
abstract: This paper describes the characteristics of a new oxygen sensitive, paramagnetic material that has some significant advantages for measurements of tissue pO2 by in vivo EPR. This paramagnetic component of Welsh coal, termed "gloxy" was found to have valuable EPR features that allow accurate measurement of low oxygen tensions in vivo; these include large oxygen-dependent changes in linewidth, a high number of paramagnetic spin centers (resulting in high signal amplitude), and stability in tissue allowing repeated pO2 measurements to be made in vivo with high precision. Renal pO2 was measured deep in the medulla region of isolated perfused kidneys and found to be lower than that in the cortex (1.7 +/- 0.05 and 7.1 +/- 0.3 mm Hg, respectively). The quality of the EPR signal obtained from the renal outer medulla and also from tumors in mice was such that the pO2 measurements were obtained with a precision of +/-3% of the measured pO2 (Kidney: 1.7 +/- 0.05 mmHg; Tumor: 1.37 +/- 0.04 mmHg). In vitro tests on the viability of cells and in vivo studies using Gloxy demonstrate the stability and inertness of this oxygen-sensitive material.
authors.affiliation: Department of Radiology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
authors.forename: P E
authors.initials: PE
authors.lastname: James
authors.forename: O Y
authors.initials: OY
authors.lastname: Grinberg
authors.forename: F
authors.initials: F
authors.lastname: Goda
authors.forename: T
authors.initials: T
authors.lastname: Panz
authors.forename: J A
authors.initials: JA
authors.lastname: O'Hara
authors.forename: H M
authors.initials: HM
authors.lastname: Swartz
mesh_terms: D000818:Animals; D016466:CHO Cells; D002244:Carbon / Q000633:toxicity; D003031:Coal; D004396:Coloring Agents / Q000633:toxicity; D006224:Cricetinae; D004578:Electron Spin Resonance Spectroscopy; D005260:Female; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D015335:Molecular Probes; D009374:Neoplasms, Experimental / Q000378:metabolism; D010100:Oxygen / Q000032:analysis*; D010313:Partial Pressure
chemical_list: D003031:Coal; D004396:Coloring Agents; D015335:Molecular Probes; C028433:chinese ink; C091644:fusinite; D002244:Carbon; D010100:Oxygen