A fundamental issue in muscle physiology is the regulation of oxygen transport to the mitochondria, since oxygen consumption can vary over a wide range, depending upon stimulation or exercise condition. Yet measuring vascular and intracellular oxygen has been extremely elusive. For vascular p02, investigators have recently noted that the water signal in leg muscle shifts with ischemia. The observation implies that the source of the shift may originate from Hb deoxygenation. If so, that paramagnetic transition during Hb deoxygenation can enhance the T2*, as functional magnetic resonance imaging studies have demonstrated, but also can shift the water line. The effect arises from the bulk magnetic susceptibility and the given limb geometry relative to main magnetic field. Consequently a calibrated curve of the water shift could then reflect the vascular p02. The project will specifically aim to determine the relationship between the chemical shift of water as a function of Mb and Hb oxidation states in analytical solutions and to establish the theoretical basis for utilizing the magnetic susceptibility induced H20 chemical shift as a p02 indicator. The results would open a new approach to measuring vascular p02 in muscle in other tissues.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21GM057355-01
Application #
2595505
Study Section
Molecular and Cellular Biophysics Study Section (BBCA)
Project Start
1998-05-01
Project End
2000-04-30
Budget Start
1998-05-01
Budget End
1999-04-30
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of California Davis
Department
Biochemistry
Type
Schools of Medicine
DUNS #
094878337
City
Davis
State
CA
Country
United States
Zip Code
95618
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Jue, Thomas; Chung, Youngran (2003) Role of myoglobin in regulating respiration. Adv Exp Med Biol 530:671-80
Ponganis, Paul J; Kreutzer, Ulrike; Sailasuta, Napapon et al. (2002) Detection of myoglobin desaturation in Mirounga angustirostris during apnea. Am J Physiol Regul Integr Comp Physiol 282:R267-72
Kreutzer, U; Mekhamer, Y; Chung, Y et al. (2001) Oxygen supply and oxidative phosphorylation limitation in rat myocardium in situ. Am J Physiol Heart Circ Physiol 280:H2030-7
Jue, T; Chung, Y; Mole, P et al. (2000) O2 and respiration in exercising human muscle. The regulation of oxidative phosphorylation in vivo. Adv Exp Med Biol 475:769-83
Tran, T K; Sailasuta, N; Kreutzer, U et al. (1999) Comparative analysis of NMR and NIRS measurements of intracellular PO2 in human skeletal muscle. Am J Physiol 276:R1682-90
Tran, T K; Sailasuta, N; Hurd, R et al. (1999) Spatial distribution of deoxymyoglobin in human muscle: an index of local tissue oxygenation. NMR Biomed 12:26-30
Mole, P A; Chung, Y; Tran, T K et al. (1999) Myoglobin desaturation with exercise intensity in human gastrocnemius muscle. Am J Physiol 277:R173-80
Chung, Y; Jue, T (1999) Regulation of respiration in myocardium in the transient and steady state. Am J Physiol 277:H1410-7
Tran, T K; Kreutzer, U; Jue, T (1998) Observing the deoxy myoglobin and hemoglobin signals from rat myocardium in situ. FEBS Lett 434:309-12

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