Brain tissue sodium is a ticking clock telling time after arterial occlusion in rat focal cerebral ischemia. Wang, Y., Hu, W., Perez-Trepichio, A. D, Ng, T. C, Furlan, A. J, Majors, A. W, & Jones, S. C Stroke, 31(6):1386–91; discussion 1392, 2000.
abstract   bibtex   
BACKGROUND AND PURPOSE: Many patients with acute stroke are excluded from receiving thrombolysis agents within the necessary time limit (3 or 6 hours from stroke onset) because they or their family members are unable provide the time of stroke onset. Brain tissue sodium concentration ([Na⊕]) increases gradually and incessantly during the initial hours of experimental focal cerebral ischemia but only in severely damaged brain regions. We propose that this steady increase in [Na⊕] can be used to estimate the time after arterial occlusion in the rat middle cerebral artery occlusion model of ischemic stroke. METHODS: Sixteen anesthetized Sprague-Dawley rats underwent permanent middle cerebral artery occlusion combined with bilateral common artery occlusion. After 100 to 450 minutes, diffusion-weighted MRI was used to generate apparent diffusion coefficient (ADC) maps, cerebral blood flow (CBF) was determined with (14)C-iodoantipyrine (in a subset of 7 animals), and the brain was frozen. Autoradiographic CBF sections and punch samples for Na⊕ analysis were obtained from the brain at the same level of the MR image. Severely at risk regions were identified with an ADC of \textless520 microm(2)/s and, in the subset, with both ADC of \textless520 microm(2)/s and CBF of \textless40 mL. 100 g(-1). min(-1). RESULTS: Both CBF and the ADC dropped quickly and remained stable in the initial hours after ischemic onset. Linear regression revealed strong linearity between [Na⊕] and time after onset, with a slope of 0.95 or 1.00 (mEq/kg DW)/min, with both ADC and ADC-plus-CBF criteria, respectively. The 95% CIs at 180 and 360 minutes were between 41 and 52 minutes. CONCLUSIONS: The time after ischemic onset can be estimated with this 2-step process. First, ADC and CBF are used to identify severely endangered regions. Second, the [Na⊕] in these regions is used to estimate time after onset. The favorable 95% CIs at the time limits for thrombolytic therapy and the availability of measurements of ADC, CBF, and [Na⊕] in humans through the use of MRI suggest that this time-estimation scheme could be used to assess the appropriateness of thrombolysis for patients who do not know when the stroke occurred.
@article{wang_brain_2000,
	title = {Brain tissue sodium is a ticking clock telling time after arterial occlusion in rat focal cerebral ischemia},
	volume = {31},
	abstract = {BACKGROUND AND PURPOSE: Many patients with acute stroke are excluded from receiving thrombolysis agents within the necessary time limit (3 or 6 hours from stroke onset) because they or their family members are unable provide the time of stroke onset. Brain tissue sodium concentration ([Na⊕]) increases gradually and incessantly during the initial hours of experimental focal cerebral ischemia but only in severely damaged brain regions. We propose that this steady increase in [Na⊕] can be used to estimate the time after arterial occlusion in the rat middle cerebral artery occlusion model of ischemic stroke. METHODS: Sixteen anesthetized Sprague-Dawley rats underwent permanent middle cerebral artery occlusion combined with bilateral common artery occlusion. After 100 to 450 minutes, diffusion-weighted MRI was used to generate apparent diffusion coefficient (ADC) maps, cerebral blood flow (CBF) was determined with (14)C-iodoantipyrine (in a subset of 7 animals), and the brain was frozen. Autoradiographic CBF sections and punch samples for Na⊕ analysis were obtained from the brain at the same level of the MR image. Severely at risk regions were identified with an ADC of {\textless}520 microm(2)/s and, in the subset, with both ADC of {\textless}520 microm(2)/s and CBF of {\textless}40 mL. 100 g(-1). min(-1). RESULTS: Both CBF and the ADC dropped quickly and remained stable in the initial hours after ischemic onset. Linear regression revealed strong linearity between [Na⊕] and time after onset, with a slope of 0.95 or 1.00 (mEq/kg DW)/min, with both ADC and ADC-plus-CBF criteria, respectively. The 95\% CIs at 180 and 360 minutes were between 41 and 52 minutes. CONCLUSIONS: The time after ischemic onset can be estimated with this 2-step process. First, ADC and CBF are used to identify severely endangered regions. Second, the [Na⊕] in these regions is used to estimate time after onset. The favorable 95\% CIs at the time limits for thrombolytic therapy and the availability of measurements of ADC, CBF, and [Na⊕] in humans through the use of MRI suggest that this time-estimation scheme could be used to assess the appropriateness of thrombolysis for patients who do not know when the stroke occurred.},
	number = {6},
	journal = {Stroke},
	author = {Wang, Y. and Hu, W. and Perez-Trepichio, A. D and Ng, T. C and Furlan, A. J and Majors, A. W and Jones, S. C},
	year = {2000},
	pages = {1386--91; discussion 1392},
}

Downloads: 0