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Measurement of Local Partial Pressure of Oxygen in the Brain Tissue under Normoxia and Epilepsy with Phosphorescence Lifetime Microscopy.

Zhang C, Bélanger S, Pouliot P, Lesage F - PLoS ONE (2015)

Bottom Line: In this work a method for measuring brain oxygen partial pressure with confocal phosphorescence lifetime microscopy system is reported.When used in conjunction with a dendritic phosphorescent probe, Oxyphor G4, this system enabled minimally invasive measurements of oxygen partial pressure (pO2) in cerebral tissue with high spatial and temporal resolution during 4-AP induced epileptic seizures.Our results reveal a correlation between the percent change in the pO2 signal during the "initial dip" and the duration of seizure-like activity, which can help localize the epileptic focus and predict the length of seizure.

View Article: PubMed Central - PubMed

Affiliation: École Polytechnique de Montréal, Department of Electrical Engineering, C.P. 6079 succ.Centre-ville, Montreal, Quebec, Canada, H3C 3A7.

ABSTRACT
In this work a method for measuring brain oxygen partial pressure with confocal phosphorescence lifetime microscopy system is reported. When used in conjunction with a dendritic phosphorescent probe, Oxyphor G4, this system enabled minimally invasive measurements of oxygen partial pressure (pO2) in cerebral tissue with high spatial and temporal resolution during 4-AP induced epileptic seizures. Investigating epileptic events, we characterized the spatio-temporal distribution of the "initial dip" in pO2 near the probe injection site and along nearby arterioles. Our results reveal a correlation between the percent change in the pO2 signal during the "initial dip" and the duration of seizure-like activity, which can help localize the epileptic focus and predict the length of seizure.

No MeSH data available.


Related in: MedlinePlus

Correlation between percent change of the initial dip at multiple locations and distances from an artery (a) Measured pO2 values of different points near an artery during the epileptic seizure (color dots), overlaid with a grayscale anatomy (with an artery shown by the red arrows). Scale bar size: 0.2mm (b) Relationship between distance from an artery for multiple points and initial dip during one epileptic seizure. The line of linear fit is y = 0.32x + 13.7, R2 = 0.7182. (C) Boxplots of slopes of linear fits in 3 mice over 25 seizures.
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pone.0135536.g007: Correlation between percent change of the initial dip at multiple locations and distances from an artery (a) Measured pO2 values of different points near an artery during the epileptic seizure (color dots), overlaid with a grayscale anatomy (with an artery shown by the red arrows). Scale bar size: 0.2mm (b) Relationship between distance from an artery for multiple points and initial dip during one epileptic seizure. The line of linear fit is y = 0.32x + 13.7, R2 = 0.7182. (C) Boxplots of slopes of linear fits in 3 mice over 25 seizures.

Mentions: To study oxidative metabolism near arteries during epileptic activity, 3 mice were recorded with measures at multiple locations near an artery that was close to the injection site. The percent pO2 value changes adjacent to the artery were significantly lower than values located farther away (an example shown in Fig 7A) despite some points being closer to the focus. Fig 7B shows a linear relationship between arterial perpendicular distance and percent of initial dip which indicates a contribution of the vascular anatomy to define the focus-surround regions. Sites that were farther from an artery, located in the capillary bed, elicited a larger decrease in tissue pO2 after onset. Extending data to the three mice, the slopes of these linear fit were combined over all seizures in Fig 7C, in all cases preserving the positive relationship. This data indicates that the vascular micro-environment contributes to oxygen consumption in the tissue during epileptic seizures.


Measurement of Local Partial Pressure of Oxygen in the Brain Tissue under Normoxia and Epilepsy with Phosphorescence Lifetime Microscopy.

Zhang C, Bélanger S, Pouliot P, Lesage F - PLoS ONE (2015)

Correlation between percent change of the initial dip at multiple locations and distances from an artery (a) Measured pO2 values of different points near an artery during the epileptic seizure (color dots), overlaid with a grayscale anatomy (with an artery shown by the red arrows). Scale bar size: 0.2mm (b) Relationship between distance from an artery for multiple points and initial dip during one epileptic seizure. The line of linear fit is y = 0.32x + 13.7, R2 = 0.7182. (C) Boxplots of slopes of linear fits in 3 mice over 25 seizures.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4549327&req=5

pone.0135536.g007: Correlation between percent change of the initial dip at multiple locations and distances from an artery (a) Measured pO2 values of different points near an artery during the epileptic seizure (color dots), overlaid with a grayscale anatomy (with an artery shown by the red arrows). Scale bar size: 0.2mm (b) Relationship between distance from an artery for multiple points and initial dip during one epileptic seizure. The line of linear fit is y = 0.32x + 13.7, R2 = 0.7182. (C) Boxplots of slopes of linear fits in 3 mice over 25 seizures.
Mentions: To study oxidative metabolism near arteries during epileptic activity, 3 mice were recorded with measures at multiple locations near an artery that was close to the injection site. The percent pO2 value changes adjacent to the artery were significantly lower than values located farther away (an example shown in Fig 7A) despite some points being closer to the focus. Fig 7B shows a linear relationship between arterial perpendicular distance and percent of initial dip which indicates a contribution of the vascular anatomy to define the focus-surround regions. Sites that were farther from an artery, located in the capillary bed, elicited a larger decrease in tissue pO2 after onset. Extending data to the three mice, the slopes of these linear fit were combined over all seizures in Fig 7C, in all cases preserving the positive relationship. This data indicates that the vascular micro-environment contributes to oxygen consumption in the tissue during epileptic seizures.

Bottom Line: In this work a method for measuring brain oxygen partial pressure with confocal phosphorescence lifetime microscopy system is reported.When used in conjunction with a dendritic phosphorescent probe, Oxyphor G4, this system enabled minimally invasive measurements of oxygen partial pressure (pO2) in cerebral tissue with high spatial and temporal resolution during 4-AP induced epileptic seizures.Our results reveal a correlation between the percent change in the pO2 signal during the "initial dip" and the duration of seizure-like activity, which can help localize the epileptic focus and predict the length of seizure.

View Article: PubMed Central - PubMed

Affiliation: École Polytechnique de Montréal, Department of Electrical Engineering, C.P. 6079 succ.Centre-ville, Montreal, Quebec, Canada, H3C 3A7.

ABSTRACT
In this work a method for measuring brain oxygen partial pressure with confocal phosphorescence lifetime microscopy system is reported. When used in conjunction with a dendritic phosphorescent probe, Oxyphor G4, this system enabled minimally invasive measurements of oxygen partial pressure (pO2) in cerebral tissue with high spatial and temporal resolution during 4-AP induced epileptic seizures. Investigating epileptic events, we characterized the spatio-temporal distribution of the "initial dip" in pO2 near the probe injection site and along nearby arterioles. Our results reveal a correlation between the percent change in the pO2 signal during the "initial dip" and the duration of seizure-like activity, which can help localize the epileptic focus and predict the length of seizure.

No MeSH data available.


Related in: MedlinePlus