In situ double-beam NADH laser fluorimetry: choice of a reference wavelength

Renault, G.; Raynal, E.; Sinet, Martine; Muffat-Joly, Martine; Berthier, J. P.; Cornillault, J.; Godard, Bruno; Pocidalo, J J

doi:10.1152/ajpheart.1984.246.4.h491

Cited by 13 publications

(14 citation statements)

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“…Previous investigators have attempted to suppress motion artifacts in the measurements of fluorescence spectroscopy of perfused hearts, using the following methods: (1) physical restriction of the heart to limit its motion with respect to the light detectors [5][6][7]; (2) using reflected light as a reference to ratio [13] or subtract [10] from the fluorescence signal; or (3) using a fluorescence standard [2] or ligand-insensitive emission wavelength [9] as the reference signal to correct for motion. With these techniques, motion artifact intensity can be significantly reduced.…”

Section: Discussionmentioning

confidence: 99%

“…Rather than do the correction in the time domain as has been done previously [10][11][12][13][14], we propose to do the correction in the frequency domain due to the fact that a magnitude Fourier transform is invariant to any time shifts between the reflected excitation and the fluorescence. The fluorescence data are thereby corrected for the appropriate frequency components of the motion.…”

Section: Theoretical Approachmentioning

confidence: 99%

“…To eliminate the influence of motion artifact on the fluorescence signal, a ratio [12,13] or subtraction [10,14] between the signal and the reference is usually used. This is under the assumption that motion causes identical fluctuations in light for both the fluorescent light signal and reflected light, and thus there is no difference in the time dependence of the detected motion in the fluorescence signal and the reference.…”

Section: Introductionmentioning

confidence: 99%

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Decreasing motion artifacts in calcium-dependent fluorescence transients from the perfused mouse heart using frequency filtering

Pan

MacGowan

et al. 2004

Cell Calcium

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A strategy has been developed for the removal of motion artifact and noise in calcium-dependent fluorescence transients from the perfused mouse heart using frequency filtering. An analytical model indicates that the spectral removal of motion artifacts is independent of the phase shift of the motion waveform in the frequency domain, and thus to the time shift (or delay) of motion in the time domain. This is based on the "shift theorem" of Fourier analysis, which avoids erroneous correction of motion artifact when using the motion signal obtained using reflectance from the heart. Several major steps are adopted to implement this model for elimination of motion as well as detection noise from the fluorescence transient signals from the calcium-sensitive probe Rhod-2. These include (1) extracting the fluorescence calcium transient signal from the raw data by using power spectrum density (PSD) in the frequency domain by subtracting the motion recorded using the reflectance of excitation light, (2) digitally filtering out the random noise using multiple bandpass filters centralized at harmonic frequencies of the transients, and (3) extracting high frequency noise with a Gaussian Kernel filter method. The processed signal of transients acquired with excessive motion artifact is comparable to transients acquired with minimal motion obtained by immobilizing the heart against the detection window, demonstrating the usefulness of this technique. Published by Elsevier Ltd.

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Section: Discussionmentioning

confidence: 99%

Section: Theoretical Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Decreasing motion artifacts in calcium-dependent fluorescence transients from the perfused mouse heart using frequency filtering

Pan

MacGowan

et al. 2004

Cell Calcium

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“…Specific optical measurements of changes in cell metabolism were first made by Chance 4 by monitoring the autofluorescence of NADH, an intrinsic fluorescing biomolecule whose concentration is sensitive to hypoxic conditions. Since then, studies have primarily examined short-term ischemia (over several minutes) that is detected locally, where fiber optic microfluorometers typically illuminate a spot less than 2 mm in diameter [5][6][7][8] . However, in our approach, we are concerned with monitoring the following parameters with clinical in vivo evaluation in mind: 1) longer periods of ischemia, for example tens of minutes to hours, 2) heterogeneous tissue response over a region larger than that previously monitored, 3) dynamic tissue response during the reperfusion phase, when the cells are given the first opportunity to recover, and 4) scattering properties of the tissue that can change due to tissue dehydration, movement during in vivo measurements, and probe-to-tissue geometry during future implementation of this technique in the clinic.…”

Section: Introductionmentioning

confidence: 99%

Autofluorescence dynamics during reperfusion following long-term renal ischemia in a rat model

et al. 2008

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Optical properties of near-surface kidney tissue were monitored in order to assess response during reperfusion to long (20 minutes) versus prolonged (150 minutes) ischemia in an in vivo rat model. Specifically, autofluorescence images of the exposed surfaces of both the normal and the ischemic kidneys were acquired during both injury and reperfusion alternately under 355 nm and 266 nm excitations. The temporal profile of the emission of the injured kidney during the reperfusion phase under 355 nm excitation was normalized to that under 266 nm as a means to account for changes in tissue optical properties independent of ischemia as well as changes in the illumination/collection geometrical parameters in future clinical implementation of this technique using a hand-held probe. The scattered excitation light signal was also evaluated as a reference signal and found to be inadequate. Characteristic time constants were extracted using fit to a relaxation model and found to have larger mean values following 150 minutes of injury. The mean values were then compared with the outcome of a chronic survival study where the control kidney had been removed. Rat kidneys exhibiting longer time constants were much more likely to fail. This may lead to a method to assess kidney viability and predict its ability to recover in the initial period following transplantation or resuscitation.

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“…The rapid development of the laser technique permitted the usage of lasers (nitrogen laser) instead of xenonor mercury lamps as the light source for the excitation of NADH [21][22][23] in combination with small diameter glassy fibres allowed the determination of changes in NADH fluorescence in deeper brain areas in vivo as well as ex vivo [24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Applications of laser-induced fluorescence spectroscopy for the determination of NADH in experimental neuroscience

Rex

Fink

2006

Laser Phys. Lett.

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There is an increasing need for continuously monitoring changes in brain metabolism and neuronal activity, respectively. The aim is to improve our understanding of mechanisms involved in physiological as well as pathophysiological and behavioural responses and to characterise drug actions. Changes of NADH concentration in the brain can be regarded as an index of changes in mitochondrial activity, which is closely related to neuronal activity. During the last decade the determination of NADH fluorescence by laser-induced fluorescence spectroscopy has become a method of choice in the study of mitochondrial metabolism in neuroscience. By now, small optical probes, providing excellent temporal and spatial resolution and the development of reliable and robust laser-based fluorescence detectors allow a widespread use in preclinical research. Besides in vitro studies, especially the assessment of changes in the NADH fluorescence in vivo has been shown to provide valuable information on brain function. Several applications are given, ranging from studying drug action or the extent of brain lesion to the measurement the time course of NADH concentration in a brain region of an awake and behaving laboratory rat. Theoretical aspects, opportunities, and limitations that have to be considered during the implementation of fluorescence spectroscopy are described. It is concluded, that measurement of NADH fluorescence by laserinduced fluorescence spectroscopy is a suitable tool for investigation of functional processes in the brain. Distribution and intensity of the NADH fluorescence in coronal rat brain slices containing the hippocampus. The data represent the intensity of the NADH fluorescence in arbitrary units and are shown as averaged data (n=5) from each measuring point, respectively

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In situ double-beam NADH laser fluorimetry: choice of a reference wavelength

Cited by 13 publications

References 0 publications

Decreasing motion artifacts in calcium-dependent fluorescence transients from the perfused mouse heart using frequency filtering

Decreasing motion artifacts in calcium-dependent fluorescence transients from the perfused mouse heart using frequency filtering

Autofluorescence dynamics during reperfusion following long-term renal ischemia in a rat model

Applications of laser-induced fluorescence spectroscopy for the determination of NADH in experimental neuroscience

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