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001-es BibID:	BIBFORM043725
Első szerző:	Reese, Torsten
Cím:	Cytoprotection does not preserve brain functionality in rats during the acute post-stroke phase despite evidence of non-infarction provided by MRI / Reese T., Pórszász R., Baumann D., Bochelen D., Boumezbeur F., McAllister K. H., Sauter A., Bjelke B., Rudin M.
Dátum:	2000
ISSN:	0952-3480
Megjegyzések:	In animal models of stroke the promise of a therapy is commonly judged from infarct size measurements, assuming that a reduction in infarct size results in reduction of the functional deficits. We have evaluated the validity of the concept that structural integrity translates into functional integrity during the acute post-stroke period (24 h). Unilateral permanent middle cerebral artery occlusion (pMCAO) in Fischer F344 rats leads to infarcts comprising the ipsilateral striatum and cortical structures, including the somatosensory cortex. Infarct volumes were assessed using magnetic resonance imaging (MRI) methods (T(2), diffusion, perfusion MRI). The functional integrity of the somatosensory cortex was assessed by functional MRI (fMRI) measuring changes in local cerebral blood volume, and by assessing the forelimb grip strength and the beam-walking performance of the animals. Treatment with the calcium antagonist isradipine (2.5 mg/kg injected s.c. immediately after pMCAO) reduced the total infarct size by more than 40% compared to vehicle-injected controls. In particular, the ipsilateral somatosensory cortex appeared normal in diffusion- and T(2)-weighted MRI images. In sham-operated rats simultaneous electrical stimulation of both forepaws led to similar activation of both somatosensory cortices, while in pMCAO animals given vehicle only the contralateral cortex showed an fMRI response. Similarly, in pMCAO rats treated with isradipine, functional activation following bilateral electrical stimulation was only detected in the contralateral somatosensory cortex despite the normal appearance of the ipsilateral cortex in MRI images. Furthermore, fMRI responses to pharmacological stimulation with bicuculline were virtually absent in the ipsilateral somatosensory cortices both in vehicle- and isradipine-treated rats. Finally there was no significant difference between vehicle- and isradipine-treated animals upon the performance of beam-walking test or in forelimb grip strength. It is concluded that during the acute (24 h) post-occlusion period, structural integrity in the somatosensory cortex revealed by MRI does not translate into preservation of function.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Nmr In Biomedicine. - 13 : 6 (2000), p. 361-370. -
További szerzők:	Pórszász Róbert (1965-) (farmakológus, klinikai farmakológus) Baumann, Diana Bochelen, Damien Boumezbeur, Fawzi McAllister, Kevin H. Sauter, André Bjelke, Börje Rudin, Markus
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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001-es BibID:	BIBFORM043727
Első szerző:	Reese, Torsten
Cím:	Regional brain activation by bicuculline visualized by functional magnetic resonance imaging. Time-resolved assessment of bicuculline-induced changes in local cerebral blood volume using an intravascular contrast agent / Reese T., Bjelke B., Pórszász R., Baumann D., Bochelen D., Sauter A., Rudin M.
Dátum:	2000
ISSN:	0952-3480
Megjegyzések:	Functional magnetic resonance imaging (fMRI) has been applied to study rat focal brain activation induced by intravenous administration of the GABA(A) antagonist bicuculline. Using magnetite nanoparticles as a blood pool contrast agent, local changes in cerebral blood volume (CBV) were assessed with high temporal (10 s) and spatial (0.35 x 0.6 mm(2)) resolutions. Upon infusion of the bicuculline region-specific increases in CBV have been observed, suggesting CBV to reflect brain activity. During the first 2 min, the signal increases were predominant in the cortex, followed by increases in other brain areas, such as the caudate putamen, thalamus and cerebellum. Ten minutes after the start of infusion, a dominant response was observed in the thalamus, while in the caudate putamen a biphasic response pattern was seen. The magnitude of the signal responses in all brain regions was dependent on the dose of bicuculline and, in general, matched the known distribution of GABA(A) binding sites. This study suggests that pharmacological fMRI, displaying brain function at the highly specific level of drug-receptor interaction, should foster our understanding of normal and pathological brain function.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Nmr In Biomedicine. - 13 : 1 (2000), p. 43-49. -
További szerzők:	Bjelke, Börje Pórszász Róbert (1965-) (farmakológus, klinikai farmakológus) Baumann, Diana Bochelen, Damien Sauter, André Rudin, Markus
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM043724
Első szerző:	Sauter, André
Cím:	Recovery of function in cytoprotected cerebral cortex in rat stroke model assessed by functional MRI / Sauter A., Reese T., Pórszász R., Baumann D., Rausch M., Rudin M.
Dátum:	2002
ISSN:	0740-3194
Megjegyzések:	Functional recovery in cytoprotected somatosensory cortex in a rat stroke model was studied using functional MRI (fMRI). Calcium antagonist treatment (isradipine) following permanent middle cerebral artery occlusion (pMCAO) reduced the infarct volume by 33 +/- 9%. The somatosensory cortex representing the forepaws was spared from infarction; however, cerebral blood flow (CBF) was significantly reduced in this area 24 hr following pMCAO. Neural function was assessed at days 1, 2, 5, and 12 following pMCAO by fMRI using electrical stimulation of both forepaws. Vehicle-treated rats did not show fMRI responses in the infarcted somatosensory cortex throughout the study. Several of the isradipine-treated animals displayed functional recovery in the cytoprotected cortex at days 5 (3/5 rats) and 12 (5/10). Correlations with fMRI signals showed that normal T2 and ADC values in the respective brain areas are necessary, but not sufficient prerequisites for functionality. Recovery of neural function is associated with normalization of CBF in the cytoprotected brain area.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Magnetic Resonance In Medicine. - 47 : 4 (2002), p. 759-765. -
További szerzők:	Reese, Torsten Pórszász Róbert (1965-) (farmakológus, klinikai farmakológus) Baumann, Diana Rausch, Martin Rudin, Markus
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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