Oxygen Dependent Quenching of Phosphorescence: A Perspective

Wilson, David F.

doi:10.1007/978-1-4615-3428-0_20

Cited by 38 publications

(30 citation statements)

References 17 publications

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“…The decay of phosphorescence is quantitatively related to the O 2 concentration as described by the SternVolmer relation. 10,11 Pd-porphyrin solution, 12 mg/kg, 12 was infused in all experimental animals, and 3 optical fibers of the multifiber phosphorimeter described previously 12 were placed near the ileal mucosa and serosa, and the kidney cortex without direct tissue contact. The measurement incorporates the Po 2 of blood vessels under the optic fiber over an area of approximately 1 cm 2 to a penetration depth of approximately 0.5 mm.…”

Section: Determination Of Microvascular Oxygen Pressurementioning

confidence: 99%

Aortic Cross-Clamping and Reperfusion in Pigs Reduces Microvascular Oxygenation by Altered Systemic and Regional Blood Flow Distribution

Siegemund

Bommel

Stegenga

et al. 2010

Anesthesia &Amp; Analgesia

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Section: Determination Of Microvascular Oxygen Pressurementioning

confidence: 99%

Aortic Cross-Clamping and Reperfusion in Pigs Reduces Microvascular Oxygenation by Altered Systemic and Regional Blood Flow Distribution

Siegemund

Bommel

Stegenga

et al. 2010

Anesthesia &Amp; Analgesia

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“…Using a multi-frequency phosphorimeter that collects data for many frequencies at the same time, it has been possible to determine oxygen distributions (oxygen histogram) using data collected in as little as 8 s. 70 The method is based on the oxygen-dependent quenching of phosphorescence emitted by albumin bound metalporphyrin complexes after pulsed light excitation, in which the decay rate is directly related to the concentration of molecular oxygen. 71 The actual size of the sampled volume is dependent on the depth of light penetration into the tissue and consequently on the excitation wavelength. The development of phosphor compounds excited at long wavelength (636 nm) has made it possible to make phosphorescence measurements through a substantial (cm) thickness of tissue.…”

Section: Techniques For the Assessment Of Tumor Oxygenationmentioning

confidence: 99%

Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications

2004

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This review paper attempts to provide an overview of the principles and techniques that are often termed electron paramagnetic resonance (EPR) oximetry. The paper discusses the potential of such methods and illustrates they have been successfully applied to measure oxygen tension, an essential parameter of the tumor microenvironment. To help the reader understand the motivation for carrying out these measurements, the importance of tumor hypoxia is first discussed: the basic issues of why a tumor is hypoxic, why these hypoxic microenvironments promote processes driving malignant progression and why hypoxia dramatically influences the response of tumors to cytotoxic treatments will be explained. The different methods that have been used to estimate the oxygenation in tumors will be reviewed. To introduce the basics of EPR oximetry, the specificity of in vivo EPR will be discussed by comparing this technique with NMR and MRI. The different types of paramagnetic oxygen sensors will be presented, as well as the methods for recording the information (EPR spectroscopy, EPR imaging, dynamic nuclear polarization). Several applications of EPR for characterizing tumor oxygenation will be illustrated, with a special emphasis on pharmacological interventions that modulate the tumor microenvironment. Finally, the challenges for transposing the method into the clinic will also be discussed.

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“…Oxygen microelectrode measurements primarily reflect tissue oxygen changes that lie somewhere between mitochondrial and capillary oxygen (Wilson, 1992;Villringer and Dirnagl, 1995). During activation by a visual stimulus at low contrast levels, consumed oxygen with low-level neural activity could be mostly replenished by drawing down the buffer reserve of mitochondrial oxygen.…”

Section: Interpretation Of Nonlinear Neurometabolic Couplingmentioning

confidence: 99%

High-Resolution Neurometabolic Coupling in the Lateral Geniculate Nucleus

Li¹,

Freeman²

2007

J. Neurosci.

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The relationships between neural and metabolic processes in activated brain regions are central to the interpretation of noninvasive imaging. To examine this relationship, we have used a specialized sensor to measure simultaneously tissue oxygen changes and neural activity in colocalized regions of the cat's lateral geniculate nucleus (LGN). Previous work with this sensor has shown that a decrease or increase in tissue oxygen can be elicited by selective control of the location and extent of neural activation in the LGN. In the current study, to evaluate the temporal integration and homogeneity of neurometabolic coupling, we have determined the relationship between multiunit extracellular neural activity and tissue oxygen responses to visual stimuli of various durations and contrasts. Our results show that the negative but not the positive oxygen response changes in an approximately linear manner with stimulus duration. The relationship between the negative oxygen response and neural activity is relatively constant with stimulus duration. Moreover, both negative and positive oxygen responses saturate at high stimulus contrast levels. Coupling between neural activity and negative oxygen responses is well described by a power law function. These results help elucidate differences between the initial negative and subsequent positive metabolic responses and may be directly relevant to questions concerning brain mapping with functional magnetic resonance imaging.

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Oxygen Dependent Quenching of Phosphorescence: A Perspective

Cited by 38 publications

References 17 publications

Aortic Cross-Clamping and Reperfusion in Pigs Reduces Microvascular Oxygenation by Altered Systemic and Regional Blood Flow Distribution

Aortic Cross-Clamping and Reperfusion in Pigs Reduces Microvascular Oxygenation by Altered Systemic and Regional Blood Flow Distribution

Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications

High-Resolution Neurometabolic Coupling in the Lateral Geniculate Nucleus

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