The American journal of physiology
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A microspectrophotometric imaging method has been developed for localized measurements of intravascular oxyhemoglobin (HbO2) saturations in microvessels from sections of quick-frozen tissue. HbO2 saturation was calculated from the absorption spectrum of red blood cells measured at five selected wavelengths in the 520- to 570-nm range. We combined the use of narrow-bandwidth interference filters and a CCD camera mounted on a microscope to obtain one gray image of the sample at each wavelength. ⋯ A constant term compensates for light loss due to scattering on red blood cells and ice crystals. The standard error in single measurements of HbO2 saturation was 5%. The present method allows off-line analysis of the HbO2 saturation distribution within a microvessel network and offers new possibilities for comparative morphological studies.