Multicomponent Analysis of Near-Infrared Spectra of Anesthetized Rat Head: (II) Quantitative Multivariate Analysis of Hemoglobin and Cytochrome Oxidase by Non-Negative Least Squares Method
There have been a number of attempts to estimate oxygen saturation in Hb (SO2) and redox state of cyt. aa3 in the living tissues by means of near-infrared (NIR) spectrophotometry (Jöbsis, 1977 and others). In the early stage of the investigation, the simple dual-wavelength technique has been used to estimate changes in So2 and redox state of cyt. aa3. However, one can not distinguish changes in O.D. due to changes in So2 and in blood volume by means of the simple dual-wavelength method. In order to estimate changes in blood volume, several authors have used changes in O.D. at 805 nm which is the isosbestic point for oxygenation-deoxygenation of Hb. However, cyt. aa2 has absorption band in this wavelength region, and thereby, quantitative analysis has been hampered (Hazeki and Tamura, 1988). In addition, there seems no appropriate wavelength-pair for estimating changes in redox state of cyt. aa2 by means of this method without interferences resulted from changes in So2 and/or in blood volume because both of the wavelengths must be isosbestic points for oxygenationdeoxygenation of Hb, and O.D. at these isosbestic points must be equal for such purpose.
KeywordsRedox State Hyperbaric Oxygen Isosbestic Point Standard Spectrum Multicomponent Analysis
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