Methods Adult male Wistar rats were subjected to transient (2-hour) middle cerebral artery occl... more Methods Adult male Wistar rats were subjected to transient (2-hour) middle cerebral artery occlusion (MCAO). Experimental groups were as follows: group 1, MCAO alone (n=5); group 2, 3x10 6 HUCBC injected into tail vein at 24 hours after MCAO (n=6) (animals of groups ...
Background and Purpose—This study uses T2* weighted imaging (T2*WI) to measure the temporal evolu... more Background and Purpose—This study uses T2* weighted imaging (T2*WI) to measure the temporal evolution of cerebral angiogenesis in rats subjected to embolic stroke up to 6 weeks after stroke onset with or without sildenafil treatment. Method—Male Wistar rats were subjected to embolic stroke and treated with saline (n10) or with sildenafil (n11), with treatment initiated at 24 hours and continued
Background—Microvascular dysfunction posttreatment of stroke with recombinant human tissue-type p... more Background—Microvascular dysfunction posttreatment of stroke with recombinant human tissue-type plasminogen activator (rht-PA) constrains the therapeutic window to 3 hours. Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) promote vascular thrombolysis and reduce the inflammation response. We therefore investigated the neuroprotective effects of a combination of atorvastatin and delayed rht-PA treatment in a rat model of embolic stroke. Methods and Results—Rats subjected to
Using magnetic resonance imaging (MRI), we investigated treatment of a rat model of embolic strok... more Using magnetic resonance imaging (MRI), we investigated treatment of a rat model of embolic stroke with rt-PA via intra-arterial (IA) and intravenous (IV) routes of administration. Rats were treated with rt-PA by either IA (n=13) or IV (n=13) routes at 3 h after stroke induction. ...
Bo pu xue za zhi = Chinese journal of microwave & radio-frequency spectroscopy / Zhongguo wu li xue hui bo pu xue zhuan ye wei yuan hui bian ji, 2014
Magnetic resonance imaging (MRI) is now a routine neuroimaging tool in the clinic. Throughout all... more Magnetic resonance imaging (MRI) is now a routine neuroimaging tool in the clinic. Throughout all phases of stroke from acute to chronic, MRI plays an important role to diagnose, evaluate and monitor the cerebral tissue undergoing stroke. This review provides a description of various MRI methods and an overview of selected MRI studies, with an embolic stroke model of rat, performed in the MRI laboratory of Department of Neurology, Henry Ford Hospital, Detroit, Michigan, US.
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism, 2005
We sought to identify magnetic resonance imaging (MRI) parameters that can identify as well as pr... more We sought to identify magnetic resonance imaging (MRI) parameters that can identify as well as predict disruption of the blood-brain barrier (BBB) after embolic stroke in the rat. Rats subjected to embolic stroke with (n=13) and without (n=13) rt-PA treatment were followed with MRI using quantitative permeability-related parameters, consisting of: transfer constant (K(i)) of Gd- DTPA, the distribution volume (V(p)) of the mobile protons, and the inverse of the apparent forward transfer rate for magnetization transfer (k(inv)), as well as the apparent diffusion coefficient of water (ADC(w)), T2, and cerebral cerebral blood flow (CBF). Tissue progressing to fibrin leakage resulting from BBB disruption and adjacent tissue were then analyzed to identify MRI markers that characterize BBB disruption. Animals were killed after final MRI measurements at 24 h after induction of embolic stroke and cerebral tissues were perfused and stained to detect fibrin leakage. K(i), V(p), and k(inv) were...
We tested the hypothesis that Niaspan (a prolonged release formulation of niacin) increases tumor... more We tested the hypothesis that Niaspan (a prolonged release formulation of niacin) increases tumor necrosis factor-α-converting enzyme (TACE) expression and Notch signaling activity and promotes arteriogenesis after stroke. Rats were subjected to middle cerebral artery ...
The mouse is an excellent model for investigations of stroke and neural injury. However, there is... more The mouse is an excellent model for investigations of stroke and neural injury. However, there is a paucity of long term functional outcome measurements for the mouse. We, therefore, developed a sensorimotor functional test (corner test) and applied this test to a model of focal cerebral ischemia in the mouse. Male C57/6J mice (n=20) were subjected to embolic middle cerebral
Journal of Cerebral Blood Flow and Metabolism, 2010
We tested the hypotheses that administration routes affect the migration and distribution of graf... more We tested the hypotheses that administration routes affect the migration and distribution of grafted neural progenitor cells (NPCs) in the ischemic brain and that the ischemic lesion plays a role in mediating the grafting process. Male Wistar rats (n=41) were subjected to 2-h middle cerebral artery occlusion (MCAo), followed 1 day later by administration of magnetically labeled NPCs. Rats with
Using magnetic resonance imaging (MRI) protocols of T(2)-, T(2)*-, diffusion- and susceptibility-... more Using magnetic resonance imaging (MRI) protocols of T(2)-, T(2)*-, diffusion- and susceptibility-weighted imaging (T2WI, T2*WI, DWI, and SWI, respectively) with a 7T system, we tested the hypothesis that treatment of embolic stroke with erythropoietin (EPO) initiated at 24 hr and administered daily for 7 days after stroke onset has benefit in repairing ischemic cerebral tissue. Adult Wistar rats were subjected to embolic stroke by means of middle cerebral artery occlusion (MCAO) and were randomly assigned to a treatment (n = 11) or a control (n = 11) group. The treated group was given EPO intraperitoneally at a dose of 5,000 IU/kg daily for 7 days starting 24 hr after MCAO. Controls were given an equal volume of saline. MRI was performed at 24 hr and then weekly for 6 weeks. MRI and histological measurements were compared between groups. Serial T2WI demonstrated that expansion of the ipsilateral ventricle was significantly reduced in the EPO-treated rats. The volume ratio of ipsilat...
Diffusion weighted magnetic resonance imaging (DWI) appears useful for the early detection of str... more Diffusion weighted magnetic resonance imaging (DWI) appears useful for the early detection of stroke (LeBihan et al., 1986; Moseley et al., 1990; Sevick et al., 1990; Shimizu et al., 1990; Moonen et al., 1991; Busza et al., 1992; Minematsu et al., 1992). In animals, the decline in ...
Journal of Cerebral Blood Flow and Metabolism, 2000
With use of magnetic resonance imaging (MRI), the effects of early and delayed treatment of embol... more With use of magnetic resonance imaging (MRI), the effects of early and delayed treatment of embolic stroke in rat with recombinant tissue plasminogen activator (rt-PA) were investigated. Rats with embolic stroke were treated with rt-PA at 1 (n = 9) or 4 (n = 7) hours after stroke onset or were untreated (n = 15). Diffusion-weighted imaging, perfusion-weighted imaging, and
Background and Purpose—This study uses T2* weighted imaging (T2*WI) to measure the temporal evolu... more Background and Purpose—This study uses T2* weighted imaging (T2*WI) to measure the temporal evolution of cerebral angiogenesis in rats subjected to embolic stroke up to 6 weeks after stroke onset with or without sildenafil treatment. Method—Male Wistar rats were subjected to embolic stroke and treated with saline (n10) or with sildenafil (n11), with treatment initiated at 24 hours and continued
Background—Microvascular dysfunction posttreatment of stroke with recombinant human tissue-type p... more Background—Microvascular dysfunction posttreatment of stroke with recombinant human tissue-type plasminogen activator (rht-PA) constrains the therapeutic window to 3 hours. Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) promote vascular thrombolysis and reduce the inflammation response. We therefore investigated the neuroprotective effects of a combination of atorvastatin and delayed rht-PA treatment in a rat model of embolic stroke. Methods and Results—Rats subjected to
Using magnetic resonance imaging (MRI), we investigated treatment of a rat model of embolic strok... more Using magnetic resonance imaging (MRI), we investigated treatment of a rat model of embolic stroke with rt-PA via intra-arterial (IA) and intravenous (IV) routes of administration. Rats were treated with rt-PA by either IA (n=13) or IV (n=13) routes at 3 h after stroke induction. ...
Bo pu xue za zhi = Chinese journal of microwave & radio-frequency spectroscopy / Zhongguo wu li xue hui bo pu xue zhuan ye wei yuan hui bian ji, 2014
Magnetic resonance imaging (MRI) is now a routine neuroimaging tool in the clinic. Throughout all... more Magnetic resonance imaging (MRI) is now a routine neuroimaging tool in the clinic. Throughout all phases of stroke from acute to chronic, MRI plays an important role to diagnose, evaluate and monitor the cerebral tissue undergoing stroke. This review provides a description of various MRI methods and an overview of selected MRI studies, with an embolic stroke model of rat, performed in the MRI laboratory of Department of Neurology, Henry Ford Hospital, Detroit, Michigan, US.
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism, 2005
We sought to identify magnetic resonance imaging (MRI) parameters that can identify as well as pr... more We sought to identify magnetic resonance imaging (MRI) parameters that can identify as well as predict disruption of the blood-brain barrier (BBB) after embolic stroke in the rat. Rats subjected to embolic stroke with (n=13) and without (n=13) rt-PA treatment were followed with MRI using quantitative permeability-related parameters, consisting of: transfer constant (K(i)) of Gd- DTPA, the distribution volume (V(p)) of the mobile protons, and the inverse of the apparent forward transfer rate for magnetization transfer (k(inv)), as well as the apparent diffusion coefficient of water (ADC(w)), T2, and cerebral cerebral blood flow (CBF). Tissue progressing to fibrin leakage resulting from BBB disruption and adjacent tissue were then analyzed to identify MRI markers that characterize BBB disruption. Animals were killed after final MRI measurements at 24 h after induction of embolic stroke and cerebral tissues were perfused and stained to detect fibrin leakage. K(i), V(p), and k(inv) were...
Methods Adult male Wistar rats were subjected to transient (2-hour) middle cerebral artery occl... more Methods Adult male Wistar rats were subjected to transient (2-hour) middle cerebral artery occlusion (MCAO). Experimental groups were as follows: group 1, MCAO alone (n=5); group 2, 3x10 6 HUCBC injected into tail vein at 24 hours after MCAO (n=6) (animals of groups ...
Background and Purpose—This study uses T2* weighted imaging (T2*WI) to measure the temporal evolu... more Background and Purpose—This study uses T2* weighted imaging (T2*WI) to measure the temporal evolution of cerebral angiogenesis in rats subjected to embolic stroke up to 6 weeks after stroke onset with or without sildenafil treatment. Method—Male Wistar rats were subjected to embolic stroke and treated with saline (n10) or with sildenafil (n11), with treatment initiated at 24 hours and continued
Background—Microvascular dysfunction posttreatment of stroke with recombinant human tissue-type p... more Background—Microvascular dysfunction posttreatment of stroke with recombinant human tissue-type plasminogen activator (rht-PA) constrains the therapeutic window to 3 hours. Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) promote vascular thrombolysis and reduce the inflammation response. We therefore investigated the neuroprotective effects of a combination of atorvastatin and delayed rht-PA treatment in a rat model of embolic stroke. Methods and Results—Rats subjected to
Using magnetic resonance imaging (MRI), we investigated treatment of a rat model of embolic strok... more Using magnetic resonance imaging (MRI), we investigated treatment of a rat model of embolic stroke with rt-PA via intra-arterial (IA) and intravenous (IV) routes of administration. Rats were treated with rt-PA by either IA (n=13) or IV (n=13) routes at 3 h after stroke induction. ...
Bo pu xue za zhi = Chinese journal of microwave & radio-frequency spectroscopy / Zhongguo wu li xue hui bo pu xue zhuan ye wei yuan hui bian ji, 2014
Magnetic resonance imaging (MRI) is now a routine neuroimaging tool in the clinic. Throughout all... more Magnetic resonance imaging (MRI) is now a routine neuroimaging tool in the clinic. Throughout all phases of stroke from acute to chronic, MRI plays an important role to diagnose, evaluate and monitor the cerebral tissue undergoing stroke. This review provides a description of various MRI methods and an overview of selected MRI studies, with an embolic stroke model of rat, performed in the MRI laboratory of Department of Neurology, Henry Ford Hospital, Detroit, Michigan, US.
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism, 2005
We sought to identify magnetic resonance imaging (MRI) parameters that can identify as well as pr... more We sought to identify magnetic resonance imaging (MRI) parameters that can identify as well as predict disruption of the blood-brain barrier (BBB) after embolic stroke in the rat. Rats subjected to embolic stroke with (n=13) and without (n=13) rt-PA treatment were followed with MRI using quantitative permeability-related parameters, consisting of: transfer constant (K(i)) of Gd- DTPA, the distribution volume (V(p)) of the mobile protons, and the inverse of the apparent forward transfer rate for magnetization transfer (k(inv)), as well as the apparent diffusion coefficient of water (ADC(w)), T2, and cerebral cerebral blood flow (CBF). Tissue progressing to fibrin leakage resulting from BBB disruption and adjacent tissue were then analyzed to identify MRI markers that characterize BBB disruption. Animals were killed after final MRI measurements at 24 h after induction of embolic stroke and cerebral tissues were perfused and stained to detect fibrin leakage. K(i), V(p), and k(inv) were...
We tested the hypothesis that Niaspan (a prolonged release formulation of niacin) increases tumor... more We tested the hypothesis that Niaspan (a prolonged release formulation of niacin) increases tumor necrosis factor-α-converting enzyme (TACE) expression and Notch signaling activity and promotes arteriogenesis after stroke. Rats were subjected to middle cerebral artery ...
The mouse is an excellent model for investigations of stroke and neural injury. However, there is... more The mouse is an excellent model for investigations of stroke and neural injury. However, there is a paucity of long term functional outcome measurements for the mouse. We, therefore, developed a sensorimotor functional test (corner test) and applied this test to a model of focal cerebral ischemia in the mouse. Male C57/6J mice (n=20) were subjected to embolic middle cerebral
Journal of Cerebral Blood Flow and Metabolism, 2010
We tested the hypotheses that administration routes affect the migration and distribution of graf... more We tested the hypotheses that administration routes affect the migration and distribution of grafted neural progenitor cells (NPCs) in the ischemic brain and that the ischemic lesion plays a role in mediating the grafting process. Male Wistar rats (n=41) were subjected to 2-h middle cerebral artery occlusion (MCAo), followed 1 day later by administration of magnetically labeled NPCs. Rats with
Using magnetic resonance imaging (MRI) protocols of T(2)-, T(2)*-, diffusion- and susceptibility-... more Using magnetic resonance imaging (MRI) protocols of T(2)-, T(2)*-, diffusion- and susceptibility-weighted imaging (T2WI, T2*WI, DWI, and SWI, respectively) with a 7T system, we tested the hypothesis that treatment of embolic stroke with erythropoietin (EPO) initiated at 24 hr and administered daily for 7 days after stroke onset has benefit in repairing ischemic cerebral tissue. Adult Wistar rats were subjected to embolic stroke by means of middle cerebral artery occlusion (MCAO) and were randomly assigned to a treatment (n = 11) or a control (n = 11) group. The treated group was given EPO intraperitoneally at a dose of 5,000 IU/kg daily for 7 days starting 24 hr after MCAO. Controls were given an equal volume of saline. MRI was performed at 24 hr and then weekly for 6 weeks. MRI and histological measurements were compared between groups. Serial T2WI demonstrated that expansion of the ipsilateral ventricle was significantly reduced in the EPO-treated rats. The volume ratio of ipsilat...
Diffusion weighted magnetic resonance imaging (DWI) appears useful for the early detection of str... more Diffusion weighted magnetic resonance imaging (DWI) appears useful for the early detection of stroke (LeBihan et al., 1986; Moseley et al., 1990; Sevick et al., 1990; Shimizu et al., 1990; Moonen et al., 1991; Busza et al., 1992; Minematsu et al., 1992). In animals, the decline in ...
Journal of Cerebral Blood Flow and Metabolism, 2000
With use of magnetic resonance imaging (MRI), the effects of early and delayed treatment of embol... more With use of magnetic resonance imaging (MRI), the effects of early and delayed treatment of embolic stroke in rat with recombinant tissue plasminogen activator (rt-PA) were investigated. Rats with embolic stroke were treated with rt-PA at 1 (n = 9) or 4 (n = 7) hours after stroke onset or were untreated (n = 15). Diffusion-weighted imaging, perfusion-weighted imaging, and
Background and Purpose—This study uses T2* weighted imaging (T2*WI) to measure the temporal evolu... more Background and Purpose—This study uses T2* weighted imaging (T2*WI) to measure the temporal evolution of cerebral angiogenesis in rats subjected to embolic stroke up to 6 weeks after stroke onset with or without sildenafil treatment. Method—Male Wistar rats were subjected to embolic stroke and treated with saline (n10) or with sildenafil (n11), with treatment initiated at 24 hours and continued
Background—Microvascular dysfunction posttreatment of stroke with recombinant human tissue-type p... more Background—Microvascular dysfunction posttreatment of stroke with recombinant human tissue-type plasminogen activator (rht-PA) constrains the therapeutic window to 3 hours. Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) promote vascular thrombolysis and reduce the inflammation response. We therefore investigated the neuroprotective effects of a combination of atorvastatin and delayed rht-PA treatment in a rat model of embolic stroke. Methods and Results—Rats subjected to
Using magnetic resonance imaging (MRI), we investigated treatment of a rat model of embolic strok... more Using magnetic resonance imaging (MRI), we investigated treatment of a rat model of embolic stroke with rt-PA via intra-arterial (IA) and intravenous (IV) routes of administration. Rats were treated with rt-PA by either IA (n=13) or IV (n=13) routes at 3 h after stroke induction. ...
Bo pu xue za zhi = Chinese journal of microwave & radio-frequency spectroscopy / Zhongguo wu li xue hui bo pu xue zhuan ye wei yuan hui bian ji, 2014
Magnetic resonance imaging (MRI) is now a routine neuroimaging tool in the clinic. Throughout all... more Magnetic resonance imaging (MRI) is now a routine neuroimaging tool in the clinic. Throughout all phases of stroke from acute to chronic, MRI plays an important role to diagnose, evaluate and monitor the cerebral tissue undergoing stroke. This review provides a description of various MRI methods and an overview of selected MRI studies, with an embolic stroke model of rat, performed in the MRI laboratory of Department of Neurology, Henry Ford Hospital, Detroit, Michigan, US.
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism, 2005
We sought to identify magnetic resonance imaging (MRI) parameters that can identify as well as pr... more We sought to identify magnetic resonance imaging (MRI) parameters that can identify as well as predict disruption of the blood-brain barrier (BBB) after embolic stroke in the rat. Rats subjected to embolic stroke with (n=13) and without (n=13) rt-PA treatment were followed with MRI using quantitative permeability-related parameters, consisting of: transfer constant (K(i)) of Gd- DTPA, the distribution volume (V(p)) of the mobile protons, and the inverse of the apparent forward transfer rate for magnetization transfer (k(inv)), as well as the apparent diffusion coefficient of water (ADC(w)), T2, and cerebral cerebral blood flow (CBF). Tissue progressing to fibrin leakage resulting from BBB disruption and adjacent tissue were then analyzed to identify MRI markers that characterize BBB disruption. Animals were killed after final MRI measurements at 24 h after induction of embolic stroke and cerebral tissues were perfused and stained to detect fibrin leakage. K(i), V(p), and k(inv) were...
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Papers by Michael Chop