BACKGROUND AND PURPOSE Arterial spin labeling (ASL) is a perfusion magnetic resonance imaging (MRI) technique that does not require contrast administration and thus may be more practical in hyperacute stroke than susceptibility-weighted bolus-tracking perfusion-weighted imaging (PWI). However, a threshold for ASL measurement of the ischemic penumbra needs to be determined. METHODS A total of ...

BACKGROUND AND PURPOSE We recently described an image analysis technique based on the temporal correlation mapping (TCM) of injected contrast agents that can be used to distinguish the hemodynamic core and hemodynamic penumbra after focal ischemia. In this study we used this technique for the first time to investigate the effects of the water-soluble AMPA receptor antagonist YM872 in permanent ...

After an ischemic stroke, neurons in the core are rapidly committed to die, whereas neuron death in the slowly developing penumbra is more amenable to therapeutic intervention. Microglia activation contributes to delayed inflammation, but because neurotoxic mechanisms in the penumbra are not well understood, we developed an in vitro model of microglia activation and propagated neuron killing. T...

Context. The physical conditions leading the sunspot penumbra decay are poorly understood so far. Aims. We investigate photospheric magnetic and velocity properties of a during phase to advance current knowledge this process. Methods. A penumbral was observed with CRISP instrument at Swedish 1 m Solar Telescope on 2016 September 4 5 in active region NOAA 12585. During these days, full-Stokes sp...

It has been well established in animal models that electrical fields generated during inter-ictal and ictal discharges are strong enough in intensity to influence action potential firing threshold and synchronization. We discuss recently published data from microelectrode array recordings of human neocortical seizures and speculate about the possible role of field effects in neuronal synchroniz...

BACKGROUND Normobaric hyperoxia (NBO) therapy is neuroprotective in acute ischemic stroke. However, how long the NBO should last to obtain optimal outcome is still unclear. Reports show that ischemic penumbra blood supply may remain compromised for a long period after ischemia-reperfusion, which would impair tissue oxygenation in ischemic penumbra. Therefore, we hypothesized that longer-lasting...

Pial arterioles actively change diameter to regulate blood flow to the cortex. However, it is unclear whether arteriole reactivity and its homeostatic role of conserving red blood cell (RBC) flux remains intact after a transient period of ischemia. To examine this issue, we measured vasodynamics in pial arteriole networks that overlie the stroke penumbra during transient middle cerebral artery ...

BACKGROUND AND PURPOSE Different strategies for neuroprotection of neonatal stroke may be required because the developing brain responds differently to hypoxia-ischemia than the mature brain. This study was designed to determine the role of caspase-dependent injury in the pathophysiology of pure focal cerebral ischemia in the immature brain. METHODS Postnatal day 7 rats were subjected to perm...

BACKGROUND With the exception of the National Institutes of Neurological Disorders and Stroke trial of recombinant tissue plasminogen activator, clinical trials in stroke have failed to show improved outcome. If further negative results such as those of recent large neuroprotective trials are to be avoided, trial methodology must be reevaluated. SUMMARY Because there is little evidence from a...

Context. Observations at 0. 1 have revealed the existence of dark cores in the bright filaments of sunspot penumbrae. Expectations are high that such dark-cored filaments are the basic building blocks of the penumbra, but their nature remains unknown. Aims. We investigate the origin of dark cores in penumbral filaments and the surplus brightness of the penumbra using an uncombed penumbral model...