scholarly journals Patterns of change in cytochrome c oxidase redox status

2004 ◽  
Vol 18 (2) ◽  
pp. 161-166
Author(s):  
Roy E. Gagnon ◽  
Andrew J. Macnab ◽  
Jacques G. LeBlanc
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Near Infrared ◽  
Circulatory Arrest ◽  
Redox Status ◽  
Serum Glucose ◽  
Cellular Level ◽  
Clinical Settings ◽  
Data Sets ◽  
Brain Response

Investigators using mono channel near infrared spectroscopy (NIRS) have reported different patterns of change in cytochrome c oxidase (Cyt) in similar studies of tissue ischaemia. We investigated whether there were distinctive differences in NIRS signals obtained simultaneously from different sampling sites during the same imposed physiological intervention within the same subject.Methods: Subjects were 36, healthy, 10 kg, commercial swine undergoing cardiopulmonary bypass to initiate 3 to 7 periods of 7.5 minutes of circulatory arrest. Each arrest was initiated at one of 81 combinations of high, normal, or low levels of core temperature, haematocrit, pH, and serum glucose. Each combination was repeated twice, yielding 162 NIRS data sets.Results: Six distinct patterns of change of Cyt were found. Typically, brain Cyt quickly became reduced shortly after the start of arrest, muscle Cyt did not start becoming reduced until after 3½ minutes of arrest, and spinal cord Cyt either did not change status or became gradually reduced throughout the period of arrest. The brain response may reflect strong oxygen dependence, while the muscle response may indicate a dependency buffered by myoglobin stores, and the spine response may indicate a low concentration of available Cyt that is too diffuse to be rapidly influenced by changes in oxygen availability.Conclusion: Multi‒channel NIRS is needed for systemic evaluation of respiration at the cellular level in clinical settings. Distinctive Cyt patterns of change occur in different organs at the same time, in response to circulatory arrest.

Redox changes in cat brain cytochrome-c oxidase after blood-fluorocarbon exchange

1990 ◽  
Vol 258 (6) ◽  
pp. H1706-H1713 ◽  
Author(s):  
M. Ferrari ◽  
D. F. Hanley ◽  
D. A. Wilson ◽  
R. J. Traystman
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Spectral Region ◽  
Near Infrared ◽  
Circulatory Arrest ◽  
Difference Spectra ◽  
Broad Absorption Band ◽  
Cat Brain

Rapid scanning near-infrared spectroscopy (730-960 nm) was utilized to determine cat brain cytochrome-c oxidase copper band by blood-perfluorochemical emulsion (Oxypherol) exchange. Spectra were carried out before, during, and after the exchange transfusion on animals with preserved somatosensory-evoked potentials and microsphere-determined cerebral blood flow. Remaining hemoglobin (less than 4% of control) was converted to carboxyhemoglobin that does not absorb in this spectral region. Difference spectra, between an hypercapnic status (8% CO2-92% O2) and postmortem, demonstrated the presence of a broad absorption band centered around 820-845 nm that could be attributed to the oxidized low potential copper ion (CuA) of cytochrome-c oxidase. However, we were unable to further oxidize this band by adding CO2 to the inspired gas mixture, but this inconsistency may be due to the near-maximal cerebral blood flow levels present in this preparation. Cytochrome oxidation by CO2 is normally attributed to increased O2 delivery to the tissue, secondary to an increased cerebral perfusion. We were unable to induce further increases in cerebral blood flow. In contrast, the cytochrome band could be reduced both by lowering fractional O2 concentration and by inducing circulatory arrest. The spectral data support the hypothesis that it is possible to quantify the cytochrome-c oxidase copper band in the near-infrared spectral region.

Temperature, Hematocrit, pH, and Glucose 4-Way ANOVA of Cytochrome C Oxidase Redox Status During Systemic Cold Circulatory Arrest in Swine

2005 ◽  
Vol 20 (2) ◽  
pp. 105-113
Author(s):  
Roy E. Gagnon ◽  
Faith A. Gagnon ◽  
Andrew J. Macnab ◽  
Jacques G. LeBlanc
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Circulatory Arrest ◽  
Redox Status

scholarly journals Image reconstruction of oxidized cerebral cytochrome C oxidase changes from broadband near-infrared spectroscopy data

2017 ◽  
Vol 4 (2) ◽  
pp. 021105 ◽  
Author(s):  
Sabrina Brigadoi ◽  
Phong Phan ◽  
David Highton ◽  
Samuel Powell ◽  
Robert J. Cooper ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Image Reconstruction ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Spectroscopy Data

scholarly journals The nature of haem a3 in the oxidized state of cytochrome c oxidase. Evidence from low-temperature magnetic-circular-dichroism spectroscopy in the near infrared region

1982 ◽  
Vol 207 (1) ◽  
pp. 167-170 ◽  
Author(s):  
A J Thomson ◽  
D G Englinton ◽  
B C Hill ◽  
C Greenwood
Keyword(s):  
Circular Dichroism ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Near Infrared ◽  
Magnetic Circular Dichroism ◽  
Infrared Region ◽  
Magnetic Circular Dichroism Spectroscopy ◽  
Near Infrared Region ◽  
Circular Dichroïsm ◽  
Inhibited Enzyme

The magnetic-circular-dichroism (m.c.d.) spectra of oxidized ‘resting’ bovine cytochrome c oxidase and the cyanide-inhibited form are reported at 5.15 T and at 4.2 K along with m.c.d. magnetization curves plotted at selected wavelengths. In both spectra there are features at 790nm and 1564nm due to Cua and haem a respectively, the e.p.r.-detectable components of the enzyme. There is a new peak at 1946nm only in the spectrum of the cyanide-inhibited enzyme. Arguments are advanced that assign this to low-spin ferric haem a3 bridged to Cua3, thereby forming a ferromagnetically coupled pair of metal ions.

Cat brain cytochrome-c oxidase redox changes induced by hypoxia after blood-fluorocarbon exchange transfusion

1995 ◽  
Vol 269 (2) ◽  
pp. H417-H424 ◽  
Author(s):  
M. Ferrari ◽  
M. A. Williams ◽  
D. A. Wilson ◽  
N. V. Thakor ◽  
R. J. Traystman ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Redox State ◽  
Near Infrared ◽  
Acute Hypoxia ◽  
Nir Spectroscopy ◽  
Severe Reduction ◽  
O2 Concentration ◽  
O2 Delivery ◽  
Sep Monitoring

We used rapid-scanning near-infrared (NIR) spectroscopy (730-960 nm) to study the effects of graded or acute hypoxia on cerebral cytochrome-c oxidase (cyt aa3) redox state in blood-perfluoro-carbon-exchanged cats with somatosensory evoked potential (SEP) monitoring. In graded hypoxia [10 min each at fractional inspiratory O2 concentration (FIO2) 0.9, 0.8, 0.7, 0.6, and 0.5], cyt aa3 reduction occurred at FIO2 0.6 when cerebral O2 delivery was < 3.5 ml.100 g-1.min-1. In acute hypoxia (FIO2 0.6 for 10 min), significant cyt aa3 reduction occurred from 5 to 10 min (cerebral O2 delivery 3.1 +/- 0.3 ml.100 g-1.min-1) and recovered with reoxygenation (FIO2 1.0). Cyt aa3 redox changes preceded or coincided with SEP alterations in both hypoxia protocols. These results demonstrate that cerebral cyt aa3 reduction occurs with severe reduction of cerebral O2 delivery, but no significant change in cerebral cyt aa3 redox state occurs with small reductions of cerebral O2 delivery. We conclude that substantial changes in cerebral cyt aa3 do not occur at physiological levels of O2 delivery and that current NIR clinical instruments would detect oxygen-dependent cerebral cyt aa3 redox changes only when O2 delivery is extremely compromised.

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