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Beta Peptide (beta + peptide)

Distribution by Scientific Domains
Life Sciences37%
Medical Sciences25%

Kinds of Beta Peptide

  • amyloid beta peptide
    		•

    Selected Abstracts

    Templating Effect of Lipid Membranes on Alzheimer's Amyloid Beta Peptide

    CHEMPHYSCHEM, Issue 2 2005
    Canay Ege Dr.
    Electrostatic influence on peptide association: The first X-ray reflectivity and grazing-incidence X-ray diffraction study on amyloid beta peptide and lipid monolayers provides insight into the differences in the interaction of the peptide with cationic and anionic monolayers (see picture). A unique templating effect is observed in the latter case. [source]

    The induction of HIF-1 reduces astrocyte activation by amyloid beta peptide

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2009
    David Schubert
    Abstract Reduced glucose metabolism and astrocyte activation in selective areas of the brain are pathological features of Alzheimer's disease (AD). The underlying mechanisms of low energy metabolism and a molecular basis for preventing astrocyte activation are not, however, known. Here we show that amyloid beta peptide (A,)-dependent astrocyte activation leads to a long-term decrease in hypoxia-inducible factor (HIF)-1, expression and a reduction in the rate of glycolysis. Glial activation and the glycolytic changes are reversed by the maintenance of HIF-1, levels with conditions that prevent the proteolysis of HIF-1,. A, increases the long-term production of reactive oxygen species (ROS) through the activation of nicotinamide adenine dinucleotide phosphate oxidase and reduces the amount of HIF-1, via the activation of the proteasome. ROS are not required for glial activation, but are required for the reduction in glycolysis. These data suggest a significant role for HIF-1,-mediated transcription in maintaining the metabolic integrity of the AD brain and identify the probable cause of the observed lower energy metabolism in afflicted areas. They may also explain the therapeutic success of metal chelators in animal models of AD. [source]

    Multiple Lyotropic Polymorphism of a Poly(ethylene glycol)-Peptide Conjugate in Aqueous Solution,

    ADVANCED MATERIALS, Issue 23 2008
    Ian W. Hamley
    Nematic and hexagonal columnar liquid crystal phase formation by a PEG,peptide conjugate is reported. The results are relevant to peptide,polymer conjugates and bionanomaterial self-assembly (with relevance to PEGylated peptides used in therapeutic applications). The use of modified fragments of the amyloid beta peptide is especially interesting with respect to amyloid fibrillization and its control. [source]

    BACE1 inhibition reduces endogenous Abeta and alters APP processing in wild-type mice,

    JOURNAL OF NEUROCHEMISTRY, Issue 6 2006
    Kouhei Nishitomi
    Abstract Accumulation of amyloid beta peptide (Abeta) in brain is a hallmark of Alzheimer's disease (AD). Inhibition of beta-site amyloid precursor protein (APP)-cleaving enzyme-1 (BACE1), the enzyme that initiates Abeta production, and other Abeta-lowering strategies are commonly tested in transgenic mice overexpressing mutant APP. However, sporadic AD cases, which represent the majority of AD patients, are free from the mutation and do not necessarily have overproduction of APP. In addition, the commonly used Swedish mutant APP alters APP cleavage. Therefore, testing Abeta-lowering strategies in transgenic mice may not be optimal. In this study, we investigated the impact of BACE1 inhibition in non-transgenic mice with physiologically relevant APP expression. Existing Abeta ELISAs are either relatively insensitive to mouse Abeta or not specific to full-length Abeta. A newly developed ELISA detected a significant reduction of full-length soluble Abeta 1,40 in mice with the BACE1 homozygous gene deletion or BACE1 inhibitor treatment, while the level of x-40 Abeta was moderately reduced due to detection of non-full-length Abeta and compensatory activation of alpha-secretase. These results confirmed the feasibility of Abeta reduction through BACE1 inhibition under physiological conditions. Studies using our new ELISA in non-transgenic mice provide more accurate evaluation of Abeta-reducing strategies than was previously feasible. [source]

    Templating Effect of Lipid Membranes on Alzheimer's Amyloid Beta Peptide

    CHEMPHYSCHEM, Issue 2 2005
    Canay Ege Dr.
    Electrostatic influence on peptide association: The first X-ray reflectivity and grazing-incidence X-ray diffraction study on amyloid beta peptide and lipid monolayers provides insight into the differences in the interaction of the peptide with cationic and anionic monolayers (see picture). A unique templating effect is observed in the latter case. [source]

    Involvement of apoptosis and cholinergic dysfunction in Alzheimer's disease

    PSYCHOGERIATRICS, Issue 2006
    Shinji TAGAMI
    Abstract As Alzheimer's disease (AD) progresses, brain atrophy becomes conspicuous, and histologically there is neuronal loss, primarily with a deficit of cholinergic neurons observed. Hitherto, the view has been that cell death, apoptosis, plays a role in this neuronal loss. Apoptosis is characterized by the morphological changes of nuclear fragmentation, chromatin condensation and cell shrinkage, with activation of caspases, members of the cysteine protease family, resulting in considerable substrate cleavage. TUNEL positive neurons have in fact been detected in AD brain, indicating increased caspase activity and resulting substrate cleavage. In AD brain, amyloid beta peptides (A,), the main constituent of senile plaque, are a specific pathological hallmark observed in extracellular spaces. In contrast, the main constituent of intracellularly observed neurofibrillary tangles (NFT) is hyperphosphorylated tau, which is observed in various neurodegenerative disorders other than AD. The viewpoint of many studies is that the A, and NFT that cause these neuropathological changes probably participate in neuronal death. However, up until now it has been thought that there was no hypothesis offering a comprehensive explanation of how the accumulation of extracellular A, and intracellular NFT leads to neuronal death. This report first covers the mechanism of apoptosis as clarified by molecular biological methods, and provides an explanation of how apoptosis could be involved in AD pathology. The subject of autophagic cell death, a type of cell death morphology that has recently been the focus of attention, is also addressed. [source]

    CCR1 is an early and specific marker of Alzheimer's disease

    ANNALS OF NEUROLOGY, Issue 5 2003
    Meredith Halks-Miller MD
    Chemokines are a diverse group of small proteins that effect cell signaling by binding to G-protein,coupled, seven-trans-membrane receptors. Our group had found previously that the chemokine receptor CCR1 was present in neurons and dystrophic processes in a small sample of Alzheimer's disease cases. This expanded immunohistochemical study shows that the number of CCR1-positive plaque-like structures in the hippocampus and entorhinal cortex is highly correlated to dementia state as measured by the clinical dementia rating score. CCR1 immunoreactivity is found in dystrophic, neurofilament-positive, synaptophysin-negative neurites that are associated with senile plaques containing amyloid beta peptides of the 1-42 species (A,42). CCR1 was not, however, associated with diffuse deposits of A,42. There was limited expression of CCR1 in neurofibrillary tangle-bearing neuritic processes. Astrocytes and microglia were typically negative for CCR1. Human brains from age-matched, nondemented individuals rarely displayed either CCR1 or A,42 immunoreactivity. Seven other types of dementing neurodegenerative diseases were examined, and all failed to demonstrate CCR1 immunopositivity unless A,42-positive plaques were also present. Thus, neuronal CCR1 is not a generalized marker of neurodegeneration. Rather, it appears to be part of the neuroimmune response to A,42-positive neuritic plaques. [source]