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.

scholarly journals Assessing cerebral blood flow, oxygenation and cytochrome c oxidase stability in preterm infants during the first 3 days after birth

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Ajay Rajaram ◽  
Daniel Milej ◽  
Marianne Suwalski ◽  
Lilian Kebaya ◽  
Matthew Kewin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Injury ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Preterm Infants ◽  
Near Infrared ◽  
Correlation Spectroscopy ◽  
The Impact ◽  
The Brain

AbstractA major concern with preterm birth is the risk of neurodevelopmental disability. Poor cerebral circulation leading to periods of hypoxia is believed to play a significant role in the etiology of preterm brain injury, with the first three days of life considered the period when the brain is most vulnerable. This study focused on monitoring cerebral perfusion and metabolism during the first 72 h after birth in preterm infants weighing less than 1500 g. Brain monitoring was performed by combining hyperspectral near-infrared spectroscopy to assess oxygen saturation and the oxidation state of cytochrome c oxidase (oxCCO), with diffuse correlation spectroscopy to monitor cerebral blood flow (CBF). In seven of eight patients, oxCCO remained independent of CBF, indicating adequate oxygen delivery despite any fluctuations in cerebral hemodynamics. In the remaining infant, a significant correlation between CBF and oxCCO was found during the monitoring periods on days 1 and 3. This infant also had the lowest baseline CBF, suggesting the impact of CBF instabilities on metabolism depends on the level of blood supply to the brain. In summary, this study demonstrated for the first time how continuous perfusion and metabolic monitoring can be achieved, opening the possibility to investigate if CBF/oxCCO monitoring could help identify preterm infants at risk of brain injury.

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.

scholarly journals Near-infrared spectroscopy measurements of cerebral blood flow and oxygen consumption following hypoxia-ischemia in newborn piglets

2006 ◽  
Vol 100 (3) ◽  
pp. 850-857 ◽  
Author(s):  
Kenneth M. Tichauer ◽  
Derek W. Brown ◽  
Jennifer Hadway ◽  
Ting-Yim Lee ◽  
Keith St. Lawrence
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Neonatal Intensive Care ◽  
Near Infrared ◽  
Hemoglobin Concentration ◽  
Oxygen Extraction Fraction ◽  
Newborn Piglets ◽  
Hypoxia Ischemia

Impaired oxidative metabolism following hypoxia-ischemia (HI) is believed to be an early indicator of delayed brain injury. The cerebral metabolic rate of oxygen (CMRO2) can be measured by combining near-infrared spectroscopy (NIRS) measurements of cerebral blood flow (CBF) and cerebral deoxy-hemoglobin concentration. The ability of NIRS to measure changes in CMRO2 following HI was investigated in newborn piglets. Nine piglets were subjected to 30 min of HI by occluding both carotid arteries and reducing the fraction of inspired oxygen to 8%. An additional nine piglets served as sham-operated controls. Measurements of CBF, oxygen extraction fraction (OEF), and CMRO2 were obtained at baseline and at 6 h after the HI insult. Of the three parameters, only CMRO2 showed a persistent and significant change after HI. Five minutes after reoxygenation, there was a 28 ± 12% (mean ± SE) decrease in CMRO2, a 72 ± 50% increase in CBF, and a 56 ± 19% decrease in OEF compared with baseline ( P < 0.05). By 30 min postinsult and for the remainder of the study, there were no significant differences in CBF and OEF between control and insult groups, whereas CMRO2 remained depressed throughout the 6-h postinsult period. This study demonstrates that NIRS can measure decreases in CMRO2 caused by HI. The results highlight the potential for NIRS to be used in the neonatal intensive care unit to detect delayed brain damage.

scholarly journals Use of 19F NMR Spectroscopy for Measurement of Cerebral Blood Flow: A Comparative Study Using Microspheres

1989 ◽  
Vol 9 (6) ◽  
pp. 886-891 ◽  
Author(s):  
David Barranco ◽  
Leslie N. Sutton ◽  
Sandra Florin ◽  
Joel Greenberg ◽  
Teresa Sinnwell ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arterial Blood ◽  
Radioactive Microsphere ◽  
Low Concentrations ◽  
Cat Brain ◽  
Nmr Techniques ◽  
High Concentrations ◽  
Washout Curves ◽  
The Brain

19F NMR was used to determine washout curves of an inert, diffusible gas (CHF3) from the cat brain. The cerebral blood flow was estimated from a bi- or tri-phasic fit to the deconvoluted wash-out curve, using the Kety-Schmidt approach. Cerebral blood flow values determined by 19F NMR show the expected responsiveness to alterations in Paco2, but are approximately 28% lower than cerebral blood flow values determined simultaneously by radioactive microsphere techniques. High concentrations of CHF3 have little effect on intracranial pressure, mean arterial blood pressure or Paco2, but cause small changes in the blood flow to certain regions of the brain. We conclude that 19F NMR techniques utilizing low concentrations of CHF3 have potential for the noninvasive measurement of cerebral blood flow.

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