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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) Grayscale angiogram of cortical pial tissue with points of interest (red dots). Scale bar size: 0.2mm (b) Corresponding temporal profiles of pO2 measured while altering FiO2. The gray segments denote the 10 minutes period during which FiO2 was increased up to 40%.
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pone.0135536.g004: (a) Grayscale angiogram of cortical pial tissue with points of interest (red dots). Scale bar size: 0.2mm (b) Corresponding temporal profiles of pO2 measured while altering FiO2. The gray segments denote the 10 minutes period during which FiO2 was increased up to 40%.

Mentions: Confocal lifetime measurements have the capability of simultaneously monitoring tissue pO2 at multiple locations. In a second animal, we obtained temporal pO2 profiles at selected tissue locations as the FiO2 was altered from 21% to 40% (Fig 4). During the first few minutes at 21% FiO2, the surplus O2 in the tissue met the metabolic demand. Our measurements (13.9±4.1 in tissue during the first few minutes) were found within the range of 5 to 25mmHg. Upon increasing the FiO2 from 21% to 40%, pO2 increased greatly and then saturated. An increase of 13.1 ± 3.1 mmHg in tissue from normoxic to hyperoxia was observed. Following this change in FiO2, pO2 values reached their peak after 191.5 ± 27.0 s in tissue.


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) Grayscale angiogram of cortical pial tissue with points of interest (red dots). Scale bar size: 0.2mm (b) Corresponding temporal profiles of pO2 measured while altering FiO2. The gray segments denote the 10 minutes period during which FiO2 was increased up to 40%.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0135536.g004: (a) Grayscale angiogram of cortical pial tissue with points of interest (red dots). Scale bar size: 0.2mm (b) Corresponding temporal profiles of pO2 measured while altering FiO2. The gray segments denote the 10 minutes period during which FiO2 was increased up to 40%.
Mentions: Confocal lifetime measurements have the capability of simultaneously monitoring tissue pO2 at multiple locations. In a second animal, we obtained temporal pO2 profiles at selected tissue locations as the FiO2 was altered from 21% to 40% (Fig 4). During the first few minutes at 21% FiO2, the surplus O2 in the tissue met the metabolic demand. Our measurements (13.9±4.1 in tissue during the first few minutes) were found within the range of 5 to 25mmHg. Upon increasing the FiO2 from 21% to 40%, pO2 increased greatly and then saturated. An increase of 13.1 ± 3.1 mmHg in tissue from normoxic to hyperoxia was observed. Following this change in FiO2, pO2 values reached their peak after 191.5 ± 27.0 s in tissue.

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