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Datta R, Heaster TM, Sharick JT, Gillette AA, Skala MC. Fluorescence lifetime imaging microscopy: fundamentals and advances in instrumentation, analysis, and applications. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-43. [PMID: 32406215 PMCID: PMC7219965 DOI: 10.1117/1.jbo.25.7.071203] [Citation(s) in RCA: 312] [Impact Index Per Article: 78.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/24/2020] [Indexed: 05/18/2023]
Abstract
SIGNIFICANCE Fluorescence lifetime imaging microscopy (FLIM) is a powerful technique to distinguish the unique molecular environment of fluorophores. FLIM measures the time a fluorophore remains in an excited state before emitting a photon, and detects molecular variations of fluorophores that are not apparent with spectral techniques alone. FLIM is sensitive to multiple biomedical processes including disease progression and drug efficacy. AIM We provide an overview of FLIM principles, instrumentation, and analysis while highlighting the latest developments and biological applications. APPROACH This review covers FLIM principles and theory, including advantages over intensity-based fluorescence measurements. Fundamentals of FLIM instrumentation in time- and frequency-domains are summarized, along with recent developments. Image segmentation and analysis strategies that quantify spatial and molecular features of cellular heterogeneity are reviewed. Finally, representative applications are provided including high-resolution FLIM of cell- and organelle-level molecular changes, use of exogenous and endogenous fluorophores, and imaging protein-protein interactions with Förster resonance energy transfer (FRET). Advantages and limitations of FLIM are also discussed. CONCLUSIONS FLIM is advantageous for probing molecular environments of fluorophores to inform on fluorophore behavior that cannot be elucidated with intensity measurements alone. Development of FLIM technologies, analysis, and applications will further advance biological research and clinical assessments.
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Affiliation(s)
- Rupsa Datta
- Morgridge Institute for Research, Madison, Wisconsin, United States
| | - Tiffany M. Heaster
- Morgridge Institute for Research, Madison, Wisconsin, United States
- University of Wisconsin, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Joe T. Sharick
- Morgridge Institute for Research, Madison, Wisconsin, United States
| | - Amani A. Gillette
- Morgridge Institute for Research, Madison, Wisconsin, United States
- University of Wisconsin, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Melissa C. Skala
- Morgridge Institute for Research, Madison, Wisconsin, United States
- University of Wisconsin, Department of Biomedical Engineering, Madison, Wisconsin, United States
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Cao R, Wallrabe H, Periasamy A. Multiphoton FLIM imaging of NAD(P)H and FAD with one excitation wavelength. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-16. [PMID: 31920048 PMCID: PMC6951488 DOI: 10.1117/1.jbo.25.1.014510] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 12/12/2019] [Indexed: 05/07/2023]
Abstract
Two-photon fluorescence lifetime imaging microscopy (FLIM) is widely used to capture autofluorescence signals from cellular components to investigate dynamic physiological changes in live cells and tissues. Among these intrinsic fluorophores, nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and flavin adenine dinucleotide (FAD)-essential coenzymes in cellular respiration-have been used as intrinsic fluorescent biomarkers for metabolic states in cancer and other pathologies. Traditional FLIM imaging for NAD(P)H, FAD, and in particular fluorescence lifetime redox ratio (FLIRR) requires a sequential multiwavelength excitation to avoid spectral bleed-through (SBT). This sequential imaging complicates image acquisition, may introduce motion artifacts, and reduce temporal resolution. Testing several two-photon excitation wavelengths in combination with optimized emission filters, we have proved a FLIM imaging protocol, allowing simultaneous image acquisition with a single 800-nm wavelength excitation for NADH and FAD with negligible SBT. As a first step, standard NADH and FAD single and mixed solutions were tested that mimic biological sample conditions. After these optimization steps, the assay was applied to two prostate cancer live cell lines: African-American (AA) and Caucasian-American (LNCaP), used in our previous publications. FLIRR result shows that, in cells, the 800-nm two-photon excitation wavelength is suitable for NADH and FAD FLIM imaging with negligible SBT. While NAD(P)H signals are decreased, sufficient photons are present for accurate lifetime fitting and FAD signals are measurably increased at lower laser power, compared with the common 890-nm excitation conditions. This single wavelength excitation allows a simplification of NADH and FAD FLIM imaging data analysis, decreasing the total imaging time. It also avoids motion artifacts and increases temporal resolution. This simplified assay will also make it more suitable to be applied in a clinical setting.
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Affiliation(s)
- Ruofan Cao
- University of Virginia, WM Keck Center for Cellular Imaging, Department of Biology, Charlottesville, Virginia, United States
| | - Horst Wallrabe
- University of Virginia, WM Keck Center for Cellular Imaging, Department of Biology, Charlottesville, Virginia, United States
| | - Ammasi Periasamy
- University of Virginia, WM Keck Center for Cellular Imaging, Department of Biology, Charlottesville, Virginia, United States
- University of Virginia, Department of Biomedical Engineering, Charlottesville, Virginia, United States
- Address all correspondence to Ammasi Periasamy, E-mail:
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Effect of temperature on FAD and NADH-derived signals and neurometabolic coupling in the mouse auditory and motor cortex. Pflugers Arch 2017; 469:1631-1649. [PMID: 28785802 DOI: 10.1007/s00424-017-2037-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 07/03/2017] [Accepted: 07/13/2017] [Indexed: 12/13/2022]
Abstract
Tight coupling of neuronal metabolism to synaptic activity is critical to ensure that the supply of metabolic substrates meets the demands of neuronal signaling. Given the impact of temperature on metabolism, and the wide fluctuations of brain temperature observed during clinical hypothermia, we examined the effect of temperature on neurometabolic coupling. Intrinsic fluorescence signals of the oxidized form of flavin adenine dinucleotide (FAD) and the reduced form of nicotinamide adenine dinucleotide (NADH), and their ratios, were measured to assess neural metabolic state and local field potentials were recorded to measure synaptic activity in the mouse brain. Brain slice preparations were used to remove the potential impacts of blood flow. Tight coupling between metabolic signals and local field potential amplitudes was observed at a range of temperatures below 29 °C. However, above 29 °C, the metabolic and synaptic signatures diverged such that FAD signals were diminished, but local field potentials retained their amplitude. It was also observed that the declines in the FAD signals seen at high temperatures (and hence the decoupling between synaptic and metabolic events) are driven by low FAD availability at high temperatures. These data suggest that neurometabolic coupling, thought to be critical for ensuring the metabolic health of the brain, may show temperature dependence, and is related to temperature-dependent changes in FAD supplies.
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Abstract
Optical microscopic imaging offers opportunities to perform noninvasive assessments of numerous parameters associated with the biochemistry, morphology, and functional state of biological samples. For example, it is possible to detect the endogenous fluorescence from a small number of important biomolecules, including NADH and FAD, which are two coenzymes involved in key metabolic pathways such as glycolysis, the Krebs cycle, and oxidative phosphorylation. Here, we review different imaging approaches to isolate the fluorescence from these chromophores in two- and three-dimensional samples and discuss the origins and potential interpretation of the observed signals in terms of cell metabolic status. Finally, we discuss the challenges and limitations of these approaches, as well as important research directions that we expect will evolve in the near future.
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Affiliation(s)
- Irene Georgakoudi
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, USA.
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Durduran T, Choe R, Baker WB, Yodh AG. Diffuse Optics for Tissue Monitoring and Tomography. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2010; 73:076701. [PMID: 26120204 PMCID: PMC4482362 DOI: 10.1088/0034-4885/73/7/076701] [Citation(s) in RCA: 561] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
This review describes the diffusion model for light transport in tissues and the medical applications of diffuse light. Diffuse optics is particularly useful for measurement of tissue hemodynamics, wherein quantitative assessment of oxy- and deoxy-hemoglobin concentrations and blood flow are desired. The theoretical basis for near-infrared or diffuse optical spectroscopy (NIRS or DOS, respectively) is developed, and the basic elements of diffuse optical tomography (DOT) are outlined. We also discuss diffuse correlation spectroscopy (DCS), a technique whereby temporal correlation functions of diffusing light are transported through tissue and are used to measure blood flow. Essential instrumentation is described, and representative brain and breast functional imaging and monitoring results illustrate the workings of these new tissue diagnostics.
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Affiliation(s)
- T Durduran
- ICFO- Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain
| | - R Choe
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - W B Baker
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
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Pogue BW, Samkoe KS, Gibbs-Strauss SL, Davis SC. Fluorescent molecular imaging and dosimetry tools in photodynamic therapy. Methods Mol Biol 2010; 635:207-22. [PMID: 20552350 PMCID: PMC3787902 DOI: 10.1007/978-1-60761-697-9_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Measurement of fluorescence and phosphorescence in vivo is readily used to quantify the concentration of specific species that are relevant to photodynamic therapy. However, the tools to make the data quantitatively accurate vary considerably between different applications. Sampling of the signal can be done with point samples, such as specialized fiber probes or from bulk regions with either imaging or sampling, and then in broad region image-guided manner. Each of these methods is described below, the application to imaging photosensitizer uptake is discussed, and developing methods to image molecular responses to therapy are outlined.
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Affiliation(s)
- Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
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7
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Sies H, Brauser B. Analysis of cellular electron transport systems in liver and other organs by absorbance and fluorescence techniques. METHODS OF BIOCHEMICAL ANALYSIS 2006; 26:285-325. [PMID: 7392961 DOI: 10.1002/9780470110461.ch7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Mayevsky A, Manor T, Pevzner E, Deutsch A, Etziony R, Dekel N, Jaronkin A. Tissue spectroscope: a novel in vivo approach to real time monitoring of tissue vitality. JOURNAL OF BIOMEDICAL OPTICS 2004; 9:1028-45. [PMID: 15447025 DOI: 10.1117/1.1780543] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Optical monitoring of various tissue physiological and biochemical parameters in real-time represents a significant new approach and a tool for better clinical diagnosis. The Tissue Spectroscope (TiSpec), developed and applied in experimental and clinical situations, is the first medical device that enables the real-time monitoring of three parameters representing the vitality of the tissue. Tissue vitality, which is correlated to the oxygen balance in the tissue, is defined as the ratio between O(2) supply and O(2) demand. The TiSpec enables the monitoring of microcirculatory blood flow (O(2) supply), mitochondrial NADH redox state (O(2) balance), and tissue reflectance, which correlates to blood volume. We describe in detail the theoretical basis for the monitoring of the three parameters and the technological aspects of the TiSpec. The comparison between the TiSpec and the existing single parameter monitoring instruments shows a statistically significant correlation as evaluated in vitro as well as in various in vivo animal models. The results presented originated in a pilot study performed in vivo in experimental animals. Further research is needed to apply this technology clinically. The clinical applications of the TiSpec include two situations where the knowledge of tissue vitality can improve clinical practice. The major application is the monitoring of "nonvital" organs of the body [i.e., the skin, gastrointestinal (G-I) tract, urethra] in emergency situations, such as in the operating rooms and intensive care units. Also, the monitoring of specific (vital) organs, such as the brain or the heart, during surgical procedure is of practical importance.
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Affiliation(s)
- Avraham Mayevsky
- Bar-Ilan University, Faculty of Life Sciences, Ramat Gan 52900, Israel.
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Georgakoudi I, Feld MS. The combined use of fluorescence, reflectance, and light-scattering spectroscopy for evaluating dysplasia in Barrett's esophagus. Gastrointest Endosc Clin N Am 2004; 14:519-37, ix. [PMID: 15261200 DOI: 10.1016/j.giec.2004.03.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Intrinsic fluorescence, diffuse reflectance, and light-scattering spectroscopy provide complementary information on biochemical and morphologic information extending potentially from the molecular to the tissue level. Model-based spectral analysis in each case yields results about specific tissue parameters in a quantitative manner.Preliminary studies demonstrate that these parameters can be used for the development of algorithms that can detect dysplastic changes in patients with Barrett's esophagus (BE) with high sensitivity and specificity. Studies validating tri-modal spectroscopy based algorithms and real-time spectroscopic data analysis are under way to provide a more accurate and extensive assessment of the potential of this approach as a clinical noninvasive tool that could improve the management and treatment of BE dysplasia.
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Affiliation(s)
- Irene Georgakoudi
- Wellman Laboratories of Photomedicine, Massachusetts General Hospital, Harvard Medical School, 40 Blossom Street, Boston, MA 02114, USA.
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Affiliation(s)
- Robert E Anderson
- Department of Neurosurgery, Thoralf M. Sundt, Jr. Neurosurgery Research Laboratory, Mayo Clinic, Rochester, Minnesota 55905, USA
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Abstract
Regional differences in the redox ratio were studied in the gerbil brain. Brains were frozen using an in situ funnel-freezing method, and sliced coronally for scanning of mitochondrial redox imaging. The relative local redox ratio of nicotinamide-adenosine dinucleotide to its reduced form was calculated from fluorescence signals of intrinsic fluorochromes, i.e. reduced nicotinamide-adenosine dinucleotide and flavoproteins, using a high resolution fluorometer developed in our laboratory. Twelve consecutive coronal images were obtained from each of 10 gerbils. The mean value of the regional redox ratio in both the cerebral and cerebellar gray matter were found to be significantly lower than that in the cerebral and cerebellar white matter (P < 0.01, Mann-Whitney test). Local differences in the redox ratio were also found among subregions of gray matter. The redox ratio in the globus pallidus was significantly higher than values in other subregions of gray matter (P < 0.01, Mann-Whitney test) We postulate that a high concentration of the reduced form of pyridine nucleotide is maintained to provide redox energy for rapid turnover of ATP in the areas of high energy consumption.
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Affiliation(s)
- A Shiino
- Department of Biochemistry and Biophysics, University of Pennsylvania, School of Medicine, Philadelphia, USA
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12
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Coremans JM, Ince C, Bruining HA, Puppels GJ. (Semi-)quantitative analysis of reduced nicotinamide adenine dinucleotide fluorescence images of blood-perfused rat heart. Biophys J 1997; 72:1849-60. [PMID: 9083689 PMCID: PMC1184379 DOI: 10.1016/s0006-3495(97)78831-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In vivo analysis of the metabolic state of tissue by means of reduced nicotinamide adenine dinucleotide (NADH) fluorimetry is disturbed by tissue movements and by hemodynamic and oximetric effects. These factors cause changes in the absorption of ultraviolet (UV) excitation light by the tissue. Many different methods have been used in the literature to compensate measured NADH fluorescence intensities for these effects. In this paper we show on theoretical grounds that the ratio of NADH fluorescence intensity and UV diffuse reflectance intensity provides a (semi-)quantitative measure of tissue NADH concentrations. This result is corroborated by experiments with tissue phantoms in which absorption and back-scattering properties were varied. Furthermore, we have verified the validity of this compensation method in isolated Langendorff-perfused rat heart preparations. In this preparation oximetric effects (of blood and tissue) are the major determinants of the metabolism-dependent UV diffuse reflectance change. Hemodynamic effects accompanying compensatory vasodilation are negligible. Movement artifacts were eliminated by simultaneously recording fluorescence and reflectance images, using a CCD camera with a biprism configuration. The results show that the NADH fluorescence/UV reflectance ratio can be used to monitor the mitochondrial redox state of the surface of intact blood-perfused myocardium.
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Affiliation(s)
- J M Coremans
- Department of General Surgery, Erasmus University Rotterdam, The Netherlands.
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Ince C, Coremans JM, Bruining HA. In vivo NADH fluorescence. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1992; 317:277-96. [PMID: 1288134 DOI: 10.1007/978-1-4615-3428-0_30] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- C Ince
- Department of Surgery, Erasmus University Rotterdam, The Netherlands
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Paddle BM, Brown G, Vincent P. Scanning fluorometer for the rapid assessment of pyridine nucleotide and flavoprotein fluorescence changes in tissues in vivo. JOURNAL OF BIOMEDICAL ENGINEERING 1986; 8:334-40. [PMID: 3762112 DOI: 10.1016/0141-5425(86)90066-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
This paper describes a scanning fluorometer which produces images in real time of the distribution of pyridine nucleotide or flavoprotein fluorescence at the surface of tissues in vivo. The basic difference between this device and others reported in the literature is that fluorescence changes at any selected point within the image can be quantified as they occur. We suggest that the apparatus has potential application in those areas of surgery where vascular replacement or repair is required and where it would be advantageous to have an immediate measure of the cellular response to a return of blood flow.
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Katz IR. Oxygen dependence of dopamine-beta-hydoxylase activity and lactate metabolism in synaptosomes from rat brain. Brain Res 1982; 231:399-409. [PMID: 7055686 DOI: 10.1016/0006-8993(82)90376-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Dopamine-beta-hydroxylase activity can be assayed in vitro in suspensions of rat hypothalamic synaptosomes by following tritium release from [2-3H]dopamine in the presence of monoamine oxidase inhibitors. The activity is inhibited by diethyldithiocarbamate, fusaric acid, amphetamine, reserpine, and desipramine. It is not sensitive to addition of tyrosine at the concentration present in cerebrospinal fluid, to added fumarate or to a rat heart extract known to contain potent inhibitors of the isolated enzyme. The reaction in air follows simple saturation kinetics with respect to variation in dopamine concentration with Km of 0.075 microM. There is reversible inhibition of activity when it is assayed at low oxygen tension. The apparent oxygen affinity is such that the enzyme does not appear saturated with respect to oxygen even at arterial oxygen tensions. Other reactions assayed exhibit less sensitivity to hypoxia: production of lactic acid from glucose becomes stimulated at 10-12 mm Hg; and oxidation of lactic acid is not inhibited at oxygen tensions above 3-4 mm Hg. Comparison of these data with the distribution of oxygen tensions present in brain suggests a basis for classifying oxygen dependent neurochemical reactions.
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Ji S, Chance B, Nishiki K, Smith T, Rich T. Micro-light guides: a new method for measuring tissue fluorescence and reflectance. THE AMERICAN JOURNAL OF PHYSIOLOGY 1979; 236:C144-56. [PMID: 426046 DOI: 10.1152/ajpcell.1979.236.3.c144] [Citation(s) in RCA: 73] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Three-way light guides containing one or more strands of 25-micron or 80-micron diameter optical fibers in each channel have been constructed and used to measure the NADH fluorescence and UV reflectance from mitochondrial suspensions, the perfused, hemoglobin-free rat liver, and the perfused beating interventricular septum of the rabbit. The optical changes measured with these so-called micro-light guides, which have channels containing one or several strands of optical fibers less than 100 micron, are comparable in magnitude with those measured using much larger conventional light guides. The effect of light scattering on the fluorescence channel has been determined and an empirical equation for correcting the fluorescence channel for light scattering has been obtained for mitochondrial suspensions. A mathematical equation characterizing the optical behavior of a two-way micro-light guide has been derived and has been shown to account satisfactorily for reflectance and fluorescence measurements of a mat surface in air.
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Steenbergen C, Deleeuw G, Barlow C, Chance B, Williamson JR. Heterogeneity of the hypoxic state in perfused rat heart. Circ Res 1977; 41:606-15. [PMID: 908108 DOI: 10.1161/01.res.41.5.606] [Citation(s) in RCA: 101] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Tissue oxygen gradients were examined in the saline-perfused rat heart by NADH fluorescence photography. In high flow hypoxia, where the coronary flow was maintained and the arterial oxygen tension was gradually reduced, oxygen extraction was virtually complete before oxygen consumption was significantly diminished. Inadequate oxygen delivery resulted in a well defined pattern of anoxic zones. The anoxic zones were several hundred microns in width, an order of magnitude greater than intercapillary distances. In low flow hypoxia (ischemia), where the arterial oxygen tension remained at its control value and the coronary flow was diminished, anoxic zones also developed, following the same pattern as in high flow hypoxia. However, in ischemia, the anoxic areas developed while the effluent oxygen tesion was significantly greater than zero. Whereas respiratory acidosis between pH 7.3 and 6.9 resulted in vasodilation, below PH 6.8 there was a marked increase in vascular resistance. Anoxic zones appeared despite only a slight change in effluent oxygen tension from the control. In high flow hypoxia, ischemia, and acidosis-induced ischemia, the anoxic zones disappeared when control perfusion conditions were restored. The data demonstrate that tissue oxygen gradients are very steep in the hypoxic state, so that ischemia and hypoxia result in discrete heterogeneous areas of anoxic tissue bounded by sharp areas where the oxygen supply is sufficient to maintain normal mitochondrial oxidative function. In these states in which oxygen delivery is less than oxygen demand, coronary perfusion appears to be regulated at the level of the arterioles rather than the capillaries.
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