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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

a) Correlation between initial dip (% change) and duration of epileptic activity. The line of linear fit was y = 0.74x − 4.35, R2 = 0.81 (b) Statistical distribution of the slopes for all mice. M1 was the name of mouse and number in the bracket was the number of seizure that was calculated. The outliers were plotted with red plus sign. The average of goodness of fit (R2) was listed for each mouse.
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pone.0135536.g008: a) Correlation between initial dip (% change) and duration of epileptic activity. The line of linear fit was y = 0.74x − 4.35, R2 = 0.81 (b) Statistical distribution of the slopes for all mice. M1 was the name of mouse and number in the bracket was the number of seizure that was calculated. The outliers were plotted with red plus sign. The average of goodness of fit (R2) was listed for each mouse.

Mentions: Because seizures had different durations, it was of interest to see if correlations between oxygenation and electrographic seizure duration were present. Linear regressions between the initial dip expressed as a percent change and seizure duration indeed showed significant correlations (an example shown in Fig 8A). This data suggest that long epileptic seizures may be accompanied by early increased oxygen consumption in the tissue. The slopes of fit between epileptic seizure duration and initial dip, distributed over spatial location measurements (shown in Fig 8B) over all seizures. Data in all mice show similar results: a positive moderate correlation was found between early metabolism in the interstitial space near the focus and duration of epileptic activities though the relationship had significant variability across the population.


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)

a) Correlation between initial dip (% change) and duration of epileptic activity. The line of linear fit was y = 0.74x − 4.35, R2 = 0.81 (b) Statistical distribution of the slopes for all mice. M1 was the name of mouse and number in the bracket was the number of seizure that was calculated. The outliers were plotted with red plus sign. The average of goodness of fit (R2) was listed for each mouse.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4549327&req=5

pone.0135536.g008: a) Correlation between initial dip (% change) and duration of epileptic activity. The line of linear fit was y = 0.74x − 4.35, R2 = 0.81 (b) Statistical distribution of the slopes for all mice. M1 was the name of mouse and number in the bracket was the number of seizure that was calculated. The outliers were plotted with red plus sign. The average of goodness of fit (R2) was listed for each mouse.
Mentions: Because seizures had different durations, it was of interest to see if correlations between oxygenation and electrographic seizure duration were present. Linear regressions between the initial dip expressed as a percent change and seizure duration indeed showed significant correlations (an example shown in Fig 8A). This data suggest that long epileptic seizures may be accompanied by early increased oxygen consumption in the tissue. The slopes of fit between epileptic seizure duration and initial dip, distributed over spatial location measurements (shown in Fig 8B) over all seizures. Data in all mice show similar results: a positive moderate correlation was found between early metabolism in the interstitial space near the focus and duration of epileptic activities though the relationship had significant variability across the population.

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