Vigabatrin: rational treatment for chronic epilepsy.
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Vigabatrin is a selective, irreversible suicide inhibitor of GABA transaminase and thus increases brain and CSF GABA. In 33 adult patients with long standing refractory epilepsy on treatment with one or two standard anti-convulsant drugs, the addition of vigabatrin up to 3g daily for eight weeks was associated with a 48.2% reduction in seizure frequency. Twenty patients who had exhibited a 50% or more reduction in frequency of one or more seizure types entered an eight week double-blind placebo controlled phase. Patients on vigabatrin maintained a 54.7% reduction of seizure frequency, whereas those on placebo showed an 18.6% increase in seizure frequency, a highly significant difference between the two groups. In the open phase, seven patients were withdrawn due to unacceptable and reversible adverse events. The commonest side effects were drowsiness, depression and mood instability, and headaches. Vigabatrin is a potentially valuable new treatment for chronic epilepsy, especially partial seizures with or without secondary generalisation. (+info)
Structure and function of non-native metal clusters in human arginase I.
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Requirement of plasminogen binding to its cell-surface receptor alpha-enolase for efficient regeneration of normal and dystrophic skeletal muscle.
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Cerebral sinus thrombosis as a potential hazard of antifibrinolytic treatment in menorrhagia.
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We describe a 42-year-old woman who developed superior sagittal and left transverse sinus thrombosis associated with prolonged epsilon-aminocaproic acid therapy for menorrhagia. This antifibrinolytic agent has been used in women with menorrhagia to promote clotting and reduce blood loss. Although increased risk of thromboembolic disease has been reported during treatment with epsilon-aminocaproic acid, cerebral sinus thrombosis has not been previously described. Careful use of epsilon-aminocaproic acid therapy is recommended. (+info)
Crystal structure of arginase from Leishmania mexicana and implications for the inhibition of polyamine biosynthesis in parasitic infections.
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Development of tolerance to the effects of vigabatrin (gamma-vinyl-GABA) on GABA release from rat cerebral cortex, spinal cord and retina.
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1. The effects of acute and chronic vigabatrin (gamma-vinyl-GABA) (GVG) administration on gamma-aminobutyric acid (GABA) levels and release in rat cortical slices, spinal cord slices and retinas were studied. 2. GVG (250 mgkg-1 i.p.) administered to rats 18 h before death (acute administration) produced an almost 3 fold increase in GABA levels of the cortex and spinal cord and a 6 fold increase in retinal GABA. The levels of glutamate, aspartate, glycine and taurine were unaffected. 3. When GVG (250 mgkg-1 i.p.) was administered daily for 17 days (chronic administration) a similar (almost 3 fold) increase in cortical GABA occurred but the increases in spinal and retinal GABA were reduced by approximately 40%. 4. Acute administration of GVG strikingly increased the potassium-evoked release (KCl 50 mM) of GABA from all three tissues. This enhanced evoked release was reduced by about 50% in tissues taken from rats that had been chronically treated with GVG. 5. Acute administration of GVG reduced GABA-transaminase (GABA-T) activity by approximately 80% in cortex and cord and by 98% in the retina. Following the chronic administration of GVG, there was a trend for GABA-T activities to recover (significant only in cortex). Acute administration of GVG had no effect on glutamic acid decarboxylase (GAD) activity in cortex or spinal cord. However, chronic treatment resulted in significant decreases in GAD activity in both the cortex and cord (35% and 50% reduction respectively). 6. The K-evoked release of glutamate, aspartate, glycine and taurine from cortical slices and the Kevoked release of glycine from spinal slices and retinas were not affected by either acute or chronic GVG treatment. 7. These experiments indicate that GVG treatment increases specifically the K-evoked release of GABA and that tolerance can develop to this enhancing effect of GVG on central GABA release. This tolerance may result from increased feedback inhibition of GAD with a consequent reduction of presynaptic GABA stores. (+info)