Xiao Yan Sun

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Families bearing mutations in the presenilin-1 (PSI) gene develop Alzheimer's disease (AD). However, the mechanism through which PS1 causes AD is unclear. The co-immunoprecipitation with PS1 in transfected COS-7 cells indicates that PSI directly interacts with endogenous beta-catenin, and the interaction requires residues 322450 of PSI and 445-676 of(More)
We examined the brains of 27 amyotrophic lateral sclerosis (ALS) patients and 50 controls by light, electron and immunoelectron microscopy. Ubiquitin-positive intraneuronal inclusions were seen in the hippocampal granular cell layer and entorhinal cortex of 7 out of the ALS patients. Similar inclusions could not be seen in the same areas in the controls.(More)
Formation of neurofibrillary tangles (NFTs) is the most common feature in several neurodegenerative diseases, including Alzheimer's disease (AD). Here we report the formation of filamentous tau aggregations having a beta-sheet structure in transgenic mice expressing mutant human tau. These mice contain a tau gene with a mutation of the frontotemporal(More)
Elevated extracellular concentrations of the excitatory transmitter glutamate are an important cause of neuronal death in a variety of disorders of the nervous system. The concentrations and rates of clearance and production of extracellular glutamate were measured in the medium of primary cultures from mouse neocortex containing neurons, astrocytes, or(More)
Amyloid-beta protein (A beta) aggregates in the brain to form senile plaques. By using thioflavin T, a dye that specifically binds to fibrillar structures, we found that metals such as Zn(II) and Cu(II) normally inhibit amyloid beta-aggregation. Another method for detecting A beta, which does not distinguish the types of aggregates, showed that these metals(More)
Axonal transport of microtubule-associated protein tau was studied in the motor fibers of the rat sciatic nerve 1-4 weeks after labeling of the spinal cord with [35S]methionine. As 60-70% of low molecular weight tau in this system was found to be insoluble in 1% Triton-containing buffer, labeled proteins in 6-mm consecutive nerve segments were first(More)
Magnetic resonance imaging (MRI) in patients with multiple sclerosis (MS) has provided major insights into the disease's natural history, and many studies have focussed on possible correlations between MRI findings and the clinical manifestations of MS. In contrast, there are few reports on possible relationships between functional imaging data and(More)
To examine the regulation of amyloid secretion in more detail, Abeta sandwich ELISAs with high sensitivity and specificity were developed. Using this technique, we measured Abeta secreted from COS7 cells transiently transfected with APP C100 in the presence of LiCl, a potent glycogen synthase kinase (GSK)-3beta inhibitor. We found that both Abetax-40 and(More)
We studied cerebral perfusion and oxygen metabolism in three patients with chorea-acanthocytosis using positron-emission tomography and oxygen-15 labeled O2 and CO2. High-field magnetic resonance imaging also was performed. Regional cerebral blood flow (rCBF) and oxygen metabolism (rCMRO2) were significantly reduced in the caudate and putamen when compared(More)
Families bearing mutations in the presenilin 1 (PS1) gene develop early onset familial Alzheimer's disease (FAD). Further, some PS1 mutants enhance secretion of the longer form of amyloid beta protein (Abeta42). We constructed cDNAs encoding human PS1 harboring 28 FAD-linked mutations, and examined the effects of the expressed PS1 mutants on Abeta42(More)