Measurement of Myocardial PO2;Physiological & Pharmacologic Interventions

Friedman, Bruce

Abstract

There has been significant progress in understanding how various physiologic parameters, such as coronary flow, perfusion pressure, diastolic pressure and influent oxygen tension, affect local myocardial pO2 as measured by EPR oximetry with lithium phthalocyanine. This in turn has allowed measurements of local oxygen tension, oxygen consumption and left ventricular work to be used for the determination and study of additional physiologic parameters, such as capillary density, and to test various models of coronary flow. It has also led to better control of experimental factors. Additional experiments have been performed to study the stability of oxygen tension in both the constant flow and constant pressure variants of the isolated perfused heart. Effects on myocardial pO2 of pharmacological interventions, such as nitric oxide which is known to play an important role in endothelial physiology, is providing new and important data. Studies using no flow ischemia show a significant increase in myocardial pO2 and coronary perfusion pressure, without significant change in oxygen consumption,left ventricular work or efficiency after brief repetitive ischemic episodes. Presumably, increased myocardial pO2 after repetitive ischemia represents increased oxygen delivery via the microcirculation due to redistribution of microvascular resistance. EPR oximetry continues to advance our understanding of myocardial oxygen levels and cardiac physiology.

Funding Agency

• Agency: National Institute of Health (NIH)
• Institute: National Center for Research Resources (NCRR)
• Type: Biotechnology Resource Grants (P41)
• Project #: 2P41RR001811-11
• Application #: 5223707
• Support Year: 11
• Fiscal Year: 1996

Publications

Hurth, Kyle M; Nilges, Mark J; Carlson, Kathryn E et al. (2004) Ligand-induced changes in estrogen receptor conformation as measured by site-directed spin labeling. Biochemistry 43:1891-907

Woodmansee, Anh N; Imlay, James A (2002) Reduced flavins promote oxidative DNA damage in non-respiring Escherichia coli by delivering electrons to intracellular free iron. J Biol Chem 277:34055-66

Denisov, Ilia G; Makris, Thomas M; Sligar, Stephen G (2002) Formation and decay of hydroperoxo-ferric heme complex in horseradish peroxidase studied by cryoradiolysis. J Biol Chem 277:42706-10

Atsarkin, V A; Demidov, V V; Vasneva, G A et al. (2001) Mechanism of oxygen response in carbon-based sensors. J Magn Reson 149:85-9

Mangels, M L; Harper, A C; Smirnov, A I et al. (2001) Investigating magnetically aligned phospholipid bilayers with EPR spectroscopy at 94 GHz. J Magn Reson 151:253-9

Breitzer, J G; Smirnov, A I; Szczepura, L F et al. (2001) Redox properties of C6S8(n-) and C3S5(n-) (n = 0, 1, 2): stable radicals and unusual structural properties for C-S-S-C bonds. Inorg Chem 40:1421-9

Denisov, I G; Hung, S C; Weiss, K E et al. (2001) Characterization of the oxygenated intermediate of the thermophilic cytochrome P450 CYP119. J Inorg Biochem 87:215-26

Kirkor, E S; Scheeline, A (2000) Nicotinamide adenine dinucleotide species in the horseradish peroxidase-oxidase oscillator. Eur J Biochem 267:5014-22

Rapoport, N; Smirnov, A I; Pitt, W G et al. (1999) Bioreduction of Tempone and spin-labeled gentamicin by gram-negative bacteria: kinetics and effect of ultrasound. Arch Biochem Biophys 362:233-41

Maringanti, S; Imlay, J A (1999) An intracellular iron chelator pleiotropically suppresses enzymatic and growth defects of superoxide dismutase-deficient Escherichia coli. J Bacteriol 181:3792-802