George Palaiologos

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Based on the selective inhibition of glutamate release in cerebellar granule cells in primary cultures by the aspartate aminotransferase inhibitor, aminooxyacetic acid, and by the ketodicarboxylate carrier inhibitor, phenylsuccinate, a novel model for synthesis of transmitter glutamate is suggested: Glutamate is formed from glutamine in the mitochondrial(More)
Phosphate-activated glutaminase (PAG) and glutamic acid decarboxylase (GAD) were assayed in homogenates and synaptosomes obtained from starved (48 hr or 120 hr) and diabetic (streptozotocin) rat brain cortex. Glutamine synthetase (GS) was assayed in homogenates, microsomal and soluble fractions, from brain cortex of similarly treated rats.l-Glutamate uptake(More)
Cetirizine, a peripheral H1 antagonist, was administered to patients with delayed pressure urticaria in a double-blind, placebo-controlled, crossover study. Efficacy in reducing pressure-induced wheals and flares was evaluated. Histologic changes were also assessed with the skin window technique in weight-induced wheals. Results showed a statistically(More)
Phosphate activated glutaminase (PAG) was assayed in whole homogenate and synaptosomes of cerebral cortex from normal or fasted for 120 h rats. The specific activity (s.a.) of PAG was found diminished by 25% in the whole homogenate from the fasted animals compared to the normal. On the contrary, fasting did not affect PAG s.a. of the synaptosomal fraction.(More)
1. Diaphragms from 48h-starved rats were incubated in Krebs-Ringer bicarbonate medium at 37degreesC for 30min and then transferred into new medium and incubated for 1, 2 and 3 h. 2. The amount of free amino acids found at the end of each time of incubation was larger than the amount at the beginning of incubation, indicating that in this system proteolysis(More)
To study the effect of agents interfering with the biosynthesis and/or the K+-evoked Ca2+-dependent release of neurotransmitter glutamate, rat cerebral slices were preincubated with Krebs-Ringer-HEPES-glucose-glutamine buffer (KRH buffer), loaded withd-[3H]aspartate and superfused with the preincubation medium in the presence or in the absence of Ca2+. The(More)
The effect of aminooxyacetic acid (AOAA), NH4 +, phenylsuccinate (Phs), ketone bodies (KB) and glutamine (Gln), that might interfere with the biosynthesis of neurotransmitter glutamate on the K+-evoked Ca2+-dependent release ofd-[3H]aspartate from rat cerebellar slices was studied. Therefore slices were preincubated in a Krebs-Ringer-bicarbonate-glucose(More)
Brain cortex slices from diabetic rats incubated in Krebs-Ringer-bicarbonate (KRB)-glucose medium show, compared to the normals, a 75% higher glutamine content. Branched chain amino acids (BCAA) added, at 0.5mM each, to this medium increase (53%) the glutamine content in the normal slices but have no effect on the glutamine content in the slices from(More)
Glutamate dehydrogenase (NAD) activity was measured in liver and diaphragm mitochondria from 48 h fasted rats. Kinetic studies were performed with diaphragm enzyme and the effects of L-leu, ADP and L-ala on the K(1)m and V(1)max for NH(4)+, and α-ketoglutarate were evaluated. L-leucine increases by 2-8 fold the V(1)max for all three substrates with no(More)