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  • Koji Aoyama, Yasunori Kimura, Wataru Takahashi, Masashi Toyoda
  • 2007
The main purpose of this paper is to study an iteration procedure for finding a common fixed point of a countable family of nonexpansive mappings in Banach spaces. We introduce a Mann type iteration procedure. Then we prove that such a sequence converges weakly to a common fixed point of a countable family of nonexpansive mappings. Moreover, we apply our(More)
Severe hypoglycemia causes neuronal death and cognitive impairment. Evidence suggests that hypoglycemic neuronal death involves excitotoxicity and DNA damage. Poly(ADP-ribose) polymerase-1 (PARP-1) normally functions in DNA repair, but promotes cell death when extensively activated by DNA damage. Cortical neuron cultures were subjected to glucose(More)
Uptake of the neurotransmitter glutamate is effected primarily by transporters expressed on astrocytes, and downregulation of these transporters leads to seizures and neuronal death. Neurons also express a glutamate transporter, termed excitatory amino acid carrier-1 (EAAC1), but the physiological function of this transporter remains uncertain. Here we(More)
Hypoglycemia-induced brain injury is a significant obstacle to optimal blood glucose control in diabetic patients. Severe hypoglycemia triggers a cascade of events in vulnerable neurons that may culminate in cell death even after glucose normalization. A key event in this cascade is the activation of poly(ADP-ribose) polymerase-1 (PARP-1). Activated PARP-1(More)
Reactive oxygen species (ROS) are by-products of the cellular metabolism of oxygen consumption, produced mainly in the mitochondria. ROS are known to be highly reactive ions or free radicals containing oxygen that impair redox homeostasis and cellular functions, leading to cell death. Under physiological conditions, a variety of antioxidant systems scavenge(More)
Due to the structural similarity to N-methyl-4-phenyl pyridinium (MPP(+)), paraquat might induce dopaminergic toxicity in the brain. However, its blood--brain barrier (BBB) penetration has not been well documented. We studied the manner of BBB penetration and neural cell uptake of paraquat using a brain microdialysis technique with HPLC/UV detection in(More)
The discovery of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) leads to the hypothesis that Parkinson's disease (PD) is maybe initiated or precipitated by environmental or endogenous toxins by the mechanism similar to that of MPTP in genetically-predisposed individuals. Endogenous analogs of MPTP, such as beta-carbolines (betaCs) and(More)
Glutathione (GSH) was discovered in yeast cells in 1888. Studies of GSH in mammalian cells before the 1980s focused exclusively on its function for the detoxication of xenobiotics or for drug metabolism in the liver, in which GSH is present at its highest concentration in the body. Increasing evidence has demonstrated other important roles of GSH in the(More)
Excitatory amino acid carrier 1 (EAAC1) is a glutamate transporter expressed on mature neurons in the CNS, and is the primary route for uptake of the neuronal cysteine needed to produce glutathione (GSH). Parkinson's disease (PD) is a neurodegenerative disorder pathogenically related to oxidative stress and shows GSH depletion in the substantia nigra (SN).(More)
Several processes by which astrocytes protect neurons during ischemia are now well established. However, less is known about how neurons themselves may influence these processes. Neurons release zinc (Zn2+) from presynaptic terminals during ischemia, seizure, head trauma, and hypoglycemia, and modulate postsynaptic neuronal function. Peak extracellular zinc(More)