Hypoxic Preconditioning Increases Blood-Brain Barrier Disruption in the Early Stages of Cerebral Ischemia.

Even though hypoxic preconditioning has been reported to produce neuroprotection, its effect on blood-brain barrier (BBB) disruption in the early stages of cerebral ischemia within the therapeutic window is not clear. Since hypoxic preconditioning increases expression of vascular endothelial growth factor (VEGF) that modulates vascular permeability, the effects of hypoxic preconditioning and VEGF on BBB permeability were investigated after one hour of focal cerebral ischemia. Rats were exposed to 8% of oxygen for two hours or room air and then 24 hours later, permanent middle cerebral artery (MCA) occlusion was performed.

Effects of rapamycin pretreatment on blood-brain barrier disruption in cerebral ischemia-reperfusion.

The mammalian target of rapamycin (mTOR) pathway is essential in neuronal survival and repair in cerebral ischemia. Decreases in blood-brain barrier (BBB) disruption are associated with a decrease in neuronal damage in cerebral ischemia. This study was performed to investigate how pre-inhibition of the mTOR pathway with rapamycin would affect BBB disruption and the size of the infarcted cortical area in the early stage of focal cerebral ischemia-reperfusion using quantitative analysis of BBB disruption.

Inhibition of neuronal nitric oxide synthase improves microregional O balance in cerebral ischemia-reperfusion.

Objectives Return of regional cerebral blood flow (rCBF) in focal cerebral ischaemia may not ensure proper distribution of blood flow to meet metabolic demand. This study was performed to determine how inhibition of neuronal nitric oxide synthase (NOS) during ischaemia-reperfusion would affect microregional O supply/consumption balances and their variation. Methods Twenty minutes before middle cerebral artery (MCA) occlusion, a NOS inhibitor 7-nitroindazole (7-NI) 50 mg/kg ip (7-NI group) or vehicle (control group) was administered.

Local O2 Balance in Cerebral Ischemia-Reperfusion Improved during Pentobarbital Compared with Isoflurane Anesthesia.

Background: Most anesthetics affect cerebral blood flow and metabolism. We compared microregional O2 balance in cerebral ischemia-reperfusion during pentobarbital and isoflurane anesthesia.

Methods: After 1 hour of middle cerebral artery occlusion and a 2-hour reperfusion under isoflurane (1.

Lower incidence of hypo-magnesemia in surgical intensive care unit patients in 2011 versus 2001.

Background: Hypo-magnesemia is described to occur in as many as 65% of intensive care unit (ICU) patients. Magnesium (Mg) is a cofactor in over 300 enzymatic reactions involving energy metabolism, protein, and nucleic acid synthesis. The membrane pump that creates the electrical gradient across the cell membrane is dependent on Mg, and it is important in the activity of electrically excitable tissues.

Effects of dexmedetomidine on microregional O2 balance during reperfusion after focal cerebral ischemia.

Background: This study was performed to determine whether there is an association between microregional O2 balance and neuronal survival in cerebral ischemia-reperfusion using dexmedetomidine, an α2-adrenoreceptor agonist and a sedative.

Methods: Rats were subjected to 1 hour middle cerebral artery occlusion and a 2-hour reperfusion. During reperfusion, normal saline (n = 14) or dexmedetomidine 1 μg/kg/minute (n = 14) was infused intravenously.

Effects of the thioredoxin-1 inhibitor PX-12 on blood-brain barrier permeability in the early stage of focal cerebral ischemia.

Background/aims: Since a thioredoxin-1 (Trx-1) inhibitor, 1-methylpropyl-2-imidazolyl disulfide (PX-12) which is an antitumor agent, significantly decreased vascular permeability in tumor xenografts within a few hours of treatment, we tested whether PX-12 would attenuate blood-brain barrier (BBB) disruption in the early stage of focal cerebral ischemia and whether its action could be affected by vascular endothelial growth factor (VEGF) which interacts with the Trx-1 system.

Methods: In rats, 40 min after intravenous infusion of either 25 mg/kg of PX-12 (PX-12 group) or normal saline (control group), a middle cerebral artery (MCA) was occluded. In half of each group, VEGF (10(-10) mol/l) was applied topically in the ischemic cortex (IC).

Cerebral ischemia and reperfusion increases the heterogeneity of local oxygen supply/consumption balance.

Background And Purpose: After cerebral vessel blockage, local blood flow and O2 consumption becomes lower and oxygen extraction increases. With reperfusion, blood flow is partially restored. We examined the effects of ischemia-reperfusion on the heterogeneity of local venous oxygen saturation in rats in order to determine the pattern of microregional O2 supply/consumption balance in reperfusion.

Effects of blockade of NMDA receptors on cerebral oxygen consumption during hyperosmolar BBB disruption in rats.

Hyperosmolar blood-brain barrier (BBB) disruption has been reported to increase cerebral O2 consumption. This study was performed to test whether blockade of N-methyl-d-aspartate (NMDA) receptor would affect cerebral O2 consumption during hyperosmolar BBB disruption. A competitive NMDA receptor antagonist CGS-19755 10mg/kg was injected iv 15min before intracarotid infusion of 25% mannitol.

Effects of cannabinoid receptor agonist WIN 55,212-2 on blood-brain barrier disruption in focal cerebral ischemia in rats.

This study was performed to investigate whether WIN 55,212-2 (WIN), a cannabinoid receptor agonist, could attenuate blood-brain barrier (BBB) disruption in focal cerebral ischemia in rats and whether the CB 1 receptor antagonist rimonabant could prevent this attenuation. A total of 0.3 or 1 mg/kg of WIN was injected intravenously before and after permanent middle cerebral artery (MCA) occlusion.