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Near-infrared (NIR) difference spectra were obtained for oxidized cytochrome c oxidase of isolated mitochondria in vitro and of cerebral tissue in situ observed through scalp and skull. The broad peaks of maximal absorption observed in both were not inconsistent with the customary assignment of an 830 nm peak. However, the ratios of the intensity of the NIR(More)
Optical spectrophotometry was used to measure changes in the oxidation-reduction state of cytochrome c oxidase in the in situ rat kidney. Alterations in the redox state of cytochrome c oxidase were monitored during variations in the amount of oxygen being delivered to the animal. Spectral analyses were performed on whole kidney, cortical tubule suspensions,(More)
The steady-state reduction/oxidation (redox) ratio of cytochrome a,a3 in the non-stressed or 'resting' cerebral cortex was compared in 'healthy' mature and aged rats and in animals with varying degrees of lung pathology present. By using noninvasive dual wavelength spectrophotometry, cytochrome a,a3 was found to be approximately 30% reduced under 'resting'(More)
We studied tumor tissue oxygenation in the BA1112 rhabdomyosarcoma using micro-electrode pO2 measurements, optical spectrophotometry, analyses of cell survival after irradiation, and 31P magnetic resonance spectroscopy (MRS). Studies were carried out in WAG/Rij/Y rats breathing normoxic, hypoxic, and hyperoxic gas mixtures with and without iv administration(More)
Rats were subjected to graded arterial hypoxia while we measured changes in the oxidation level of cytochrome c oxidase (cytochrome aa3) in the brain by a non-invasive, optical technique. The experiments were terminated at different arterial oxygen tensions (hypoxic levels) and the in vivo observations were compared with in vitro measured changes in(More)
Cyanide-induced cytotoxicity is primarily a result of inhibition of O2 uptake by the terminal enzyme of the mitochondrial respiratory chain, cytochrome-c oxidase (cytochrome aa3). The oxidase in the brain is highly vulnerable to cyanide cytotoxicity, but few studies have evaluated the effects of cyanide on cerebral oxygen metabolism. In the present study,(More)
The sensitivity of the brain to cyanide-induced histotoxic hypoxia and the protective effects of known cyanide antagonists, have been assessed in vivo by reflectance spectrophotometry. Cyanide-related changes in cytochrome a,a3 (cytochrome c oxidase) oxidation-reduction (redox) state, tissue hemoglobin saturation, and local blood volume were continuously(More)
Differential near infrared spectrophotometry was used to monitor sequential in vivo alterations in cerebral hemoglobin saturation, blood volume, and cytochrome c oxidase reduction/oxidation responses during and after a period of incomplete transient ischemia (acute, reversible common carotid artery occlusion). In this study the rat brain was monitored(More)