title: Quantitative evaluation of optical reflection spectra of blood-free perfused guinea pig brain using a nonlinear multicomponent analysis.
abstract: After developing a blood-free perfused preparation of the guinea pig brain a nonlinear multicomponent analysis (NLMCA) of the reflection spectra of the brain surface was worked out by which the redox state of cytochrome aa3, c, and b could be evaluated quantitatively and almost continuously. The NLMCA allowed to simulate the tissue reflection spectra in such a way that only a small statistical error remained between the recorded and the computed spectra. Using redox states of cytochrome aa3 and c as an intracellular oxygen probe it was found that in order to supply the guinea brain with sufficient oxygen by a saline medium equilibrated with 95% oxygen and 5% CO2 the temperature had to be reduced to 18-20 degrees C. At this temperature cytochrome aa3 was 95% oxidized.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D003580:Cytochromes / Q000378:metabolism*; D006168:Guinea Pigs; D008027:Light; D008433:Mathematics; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010100:Oxygen; D010477:Perfusion; D012542:Scattering, Radiation; D013053:Spectrophotometry; D013696:Temperature
chemical_list: D003580:Cytochromes; D010100:Oxygen