• Journal of Korean Neurosurgical Society
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• v.29 no.6
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• pp.719-724
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• 2000

Objectives : It has been reported that the presence of a pharmacologically inactive foreign substance, polystyrene latex bead, in subarachnoid space activates a non-specific immunological response and elicits arterial narrowing. Recently the activation of potassium($K^+$) channels may be of benefit in relieving cerebral vasospasm. The present study examined the effects of systemic administration of a ATP-sensitive $K^+$ channel activator, cromakalim, on the polystyrene latex bead-induced cerebral vasospasm. Methods : The spasm models similar to that caused by subarachnoid blood injection were created by injection of bead into rabbit cisterna magna. Intravenous injections of cromakalim were administered twice daily(bid) 30 minutes after induction of vasospasm. Animals were killed by perfusion-fixation 2 days after vasospasm. Basilar arteries were removed and sectioned, and the luminal cross-sectional areas were measured. Results : Injection of bead elicited an arterial constriction, reducing arterial diameter to 33.3% of resting tone. Cromakalim inhibited bead-induced constriction at a dose of 0.3mg/kg(Mann-Whitney test, p<0.01). Conclusion : These results support the concept that the cellular events triggered by inactivation of ATP-sensitive $K^+$ channels are responsible for the pathogenesis of vasospasm. The findings also indicate that cromakalim represents a potential therapeutic agents for the treatment of cerebral vasospasm.

• Applied Chemistry for Engineering
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• v.25 no.3
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• pp.274-280
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• 2014

Polysulfone (PSf) hollow fiber membranes were prepared via the nonsolvent induced phase separation technique. The cosolvent of ${\gamma}$-butyrolactone (GBL) was added to the polymer solution containing a mixture of PSf and N,N-dimethylacetamide (DMAc). Water was utilized as a precipitation nonsolvent. The morphology of prepared membranes was investigated using a field emission scanning electron microscopy. The fabricated membrane showed a typical asymmetric structure such as the dense layer on the porous support layer by the addition of GBL to the polymer solution. As the concentration of GBL increased, the asymmetric porous structure was shown to be more intensified. It was thought that the added GBL played a role of enhancing the liquid-liquid phase separation of the polymer solution, since the cosolvent of GBL might change the thermodynamic solubility parameter of the doping solution. Permeation properties through the prepared hollow fiber membranes were characterized by measuring the pure water flux and the solute rejection using $0.05{\mu}m$ polystyrene latex (PSL) beads. Experimental results revealed that the use of PEG as the internal coagulant enhanced the pure water flux up to 130 times compared to the use of EG while the rejection of the PSL beads decreased only 5%.