Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10636 (tau protein)
 5,110 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tau protein is a major component of paired helical filaments (PHFs) which constitute the characteristic neurofibrillary tangle lesions observed in Alzheimer's disease. Two tau mAbs have been produced which show distinct patterns of immunoreactivity with intact human tau and with tau incorporated in PHFs. The mAb 423 recognises PHFs but not human tau on immunoblots whereas mAb 7/51 reacts with human tau but its epitope is buried within the PHF and is only exposed after formic acid treatment. A competitive ELISA has been developed for both of these mAbs and these have been used to quantify the two distinct tau epitopes in PHFs. Samples containing antigen are incubated with horseradish peroxidase-conjugated mAb at 4 degrees C for 16 h and non-adsorbed antibody then measured by binding, at 37 degrees C for 1 h, to a fragment of tau coated on microtitre plates. Bound enzyme-labelled antibody is measured kinetically using a spectrophotometer capable of automatically mixing the samples throughout a 2-min incubation with substrate and chromogen. The interfacing of the plate reader with a computer permits competitive curves to be plotted automatically using Softmax. Curves are fitted using a 4-parameter logistic algorithm which allows one to determine the relative immunoreactivity for different samples. The application of these assays to monitoring biochemical fractions and quantifying distinct immunochemical presentations of tau protein with these two mAbs is described.
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PMID:Competitive ELISA for the measurement of tau protein in Alzheimer's disease. 170 71

Three new human medulloblastoma (MB) cell lines (D384 Med, D425 Med, and D458 Med) and their transplantable xenografts were examined for antigenic expression with antibodies against neuroectodermal antigens, cytoskeletal proteins, neuroendocrine markers, glioma-associated antigens, tenascin, human lymphocyte antigen molecules, epidermal growth factor receptor, and T-cell antigen by indirect immunofluorescence, avidin-biotin complex peroxidase immunohistochemistry, and immunoblot methods. We found that each of the three cell lines expressed vimentin; low-, middle-, and high-molecular-weight neurofilament proteins; and the synaptic vesicle membrane glycoprotein synaptophysin. Each of the cell lines also reacted with antibodies against neural cell adhesion molecules, but none of them were positive for antibodies against glial fibrillary acidic protein, keratin, microtubule-associated protein tau and microtubule-associated protein 2, human lymphocyte antigen-DR, epidermal growth factor receptor, and T-cell antigen. Immunoreactivities with anti-tenascin and anti-glioma-associated antibodies were variable in these cell lines. Anti-human lymphocyte antigen-A,B and anti-beta 2-microglobulin antibodies reacted with xenografts of D384 Med and D425 Med and were weakly positive for a small population of D384 Med cultured cells. In summary, the detection of neurofilament proteins and synaptophysin and the absence of glial fibrillary acidic protein provide strong evidence for a neuronal phenotype of D384 Med, D425 Med, and D458 Med.
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PMID:Differentiation characteristics of newly established medulloblastoma cell lines (D384 Med, D425 Med, and D458 Med) and their transplantable xenografts. 190 13

Alzheimer's neurofibrillary tangles (NFT) and paired helical filaments (PHF) were found in the pheochromocytoma cells of the adrenal gland removed from a 54-year-old female. By electron microscopy they were identical to those found in the brains affected by dementia of Alzheimer type. In the tumor cells, most of the PHF were found dispersed loosely in the cytoplasm, while typical NFT were infrequent. By immunoelectron microscopy using peroxidase-antiperoxidase method, both NFT and dispersed PHF were stained positively with a polyclonal antiserum to human tau protein. This is the first observation of NFT and PHF in paraneuronal tumor cells. The patient has no obvious Alzheimer's disease.
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PMID:Alzheimer's neurofibrillary tangles and paired helical filaments in the pheochromocytoma cells of the adrenal medulla--electron microscopic and immunoelectron microscopic observations. 212 83

I have used Tau-1 and Tau-2, two monoclonal antibodies against tau protein, to study at the electron microscopic level the tau immunoreactivity in 8 cases with dementia of the Alzheimer type, using the peroxidase-antiperoxidase technique and formalin-fixed autopsy and biopsy brain tissues. In neurons and astrocytes, excessive amounts of tau immunoreactivity were noted in association with ribosomes. The Alzheimer's abnormal filaments in neurofibrillary tangles in neuronal perikarya, in senile plaques, and in a multitude of abnormal neuropil neurites were frequently stained intensely. However, many neurons contained either stained ribosomes only or stained ribosomes and unstained abnormal filaments both scattered and in neurofibrillary tangles. In all locations, the immunostained abnormal filaments were straight without appreciable periodic constrictions and, on cross-section, had a tubular appearance with stained walls, frequently demonstrable unstained lumens and an accentuation of staining intensity at the periphery. In addition, conventional electron microscopy showed that formalin-fixed and glutaraldehyde-fixed neurofibrillary tangles were made of compactly arranged straight filaments and loosely arranged paired helical filaments, whereas osmium tetroxide-fixed neurofibrillary tangles were made almost exclusively of paired helical filaments. These findings suggest that: (a) localization of excessive tau immunoreactivity with ribosomes might be the primary event and association of detectable tau immunoreactivity with already assembled filaments might be an epiphenomenon; and (b) the mode of fixation and subsequent preparatory procedures might alter the morphology of the Alzheimer's abnormal filaments.
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PMID:Tau protein immunoreactivity in dementia of the Alzheimer type: II. Electron microscopy and pathogenetic implications. Effects of fixation on the morphology of the Alzheimer's abnormal filaments. 249 88

Submitted for the study were 116 autopsy brains, from 65 non-demented people, 24 patients with dementia of Alzheimer type (DAT) and 27 patients with vascular dementia, aged between 50 s and 100 s. Formalin-fixed, paraffin-embedded coronal sections of the brains at the level of the lateral geniculate body were immunohistochemically stained with the avidin-biotin-peroxidase complex procedure, using the anti-bodies to tau protein purified from human brains (anti-tau) as the primary antibodies. Alzheimer neurofibrillary tangles (NFTs) which were specifically and selectively stained by anti-tau were semiquantitatively counted in the areas of the hippocampus, parahippocampal gyrus and lateral occipitotemporal gyrus. The results were as follows: 1) In non-demented subjects, NFTs in the hippocampus and parahippocampal gyrus were scanty in the 50 s: they increased markedly after 60 years until 90 as the patients' age increased; they tended to decrease over 90 years. In contrast, NFTs in the lateral occipitotemporal gyrus remained none or scanty, always less than 10/mm2 field, throughout the ages between 50 s and 100 s. 2) In DAT cases, NFTs in the hippocampus and parahippocampal gyrus were numerous in all cases at any ages. NFTs in the lateral occipitotemporal gyrus were also many, and always more than 10/mm2 in all cases except a few ones over 80 years of age. The numbers of NFTs of the three areas were significantly higher in DAT cases than in non-demented subjects. 3) In most cases of vascular dementia, the density and distribution pattern of NFTs were essentially similar to those of non-demented subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[A semiquantitative study on Alzheimer neurofibrillary tangles demonstrated immunohistochemically with anti-tau antibodies, in the brains of non-demented and demented old people]. 250 32

In the neurofibrillary pathology of Alzheimer's disease (AD), neurofibrillary tangles (NFTs) contain paired helical filaments (PHFs) as their major fibrous component. Abnormally hyperphosphorylated, microtubule-associated protein tau is the major protein subunit of PHFs. A recent in vitro study showed that PHF tangles from AD brains are highly glycosylated, whereas no glycan is detected in normal tau. Deglycosylation of PHF tangles converts them into bundles of straight filaments and restores their accessibility to microtubules. We showed that PHF tangles from AD brain tissue were associated with specific glycan molecules by double immunostaining with peroxidase and alkaline phosphatase labeling. Intracellular tangles and dystrophic neurites in a neuritic plaque with abnormally hyperphosphorylated tau, detected with the monoclonal antibodies AT-8 and anti-tau-2, were also positive with lectin Galanthus nivalis agglutinin (GNA) which recognizes both the N- and O-glycosidically linked saccharides. Colocalization was not seen in the extracellular tangles and amyloid deposition, suggesting that the glycosylation of tau might be associated with the early phase of insoluble NFT formation. Thus, although abnormal phosphorylation might promote aggregation of tau and inhibition of the assembly of microtubules, glycosylation mediated by a GNA-positive glycan appears to be responsible for the formation of the PHF structures in vivo.
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PMID:Glycosylation of microtubule-associated protein tau in Alzheimer's disease brain. 1037 83

The precursor of the non-Abeta-component of Alzheimer's disease (AD) amyloid (NACP, alpha-synuclein) aggregates into insoluble filaments of Lewy bodies (LBs) in Parkinson's disease (PD) and dementia with LBs (DLB). The microtubule-associated protein tau is an integral component of filaments of neurofibrillary tangles (NFTs). NFTs are occasionally found in brains of PD and DLB; however, the presence of NFTs or tau-epitopes within LB-containing neurons is rare. Double-immunofluorescence study and peroxidase-immunohistochemical study in serial sections, performed to examine the co-localization of tau- and NACP-epitopes in the brainstem of PD and DLB, demonstrated that four different epitopes of tau including phosphorylation-dependent and independent ones were present in a minority of LBs, but more often than previously considered. A tau (tau2)-epitope was localized to filaments in the outer layers of brainstem-type LBs by immunoelectron microscopy. Therefore, we conclude that tau is incorporated into filaments in certain LBs. Extensive investigation has enabled us to classify this co-localization into four types: type 1, LBs with ring-shaped tau-immunoreactivity; type 2, LBs surrounded by NFTs; type 3, NACP- and tau-immunoreactive filamentous and granular masses; and type 4, NACP- and tau-immunoreactive dystrophic neurites. This study raises a new question whether aggregation and hyperphosphorylation of tau in PD and DLB are triggered by the collapse of intraneuronal organization of microtubules due to NACP-filament aggregation in neuronal perikarya and axons.
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PMID:Cellular co-localization of phosphorylated tau- and NACP/alpha-synuclein-epitopes in lewy bodies in sporadic Parkinson's disease and in dementia with Lewy bodies. 1052 10

There is a great deal of evidence to support a pathogenic role of oxidative stress in Alzheimer's disease (AD), but the sources of reactive oxygen species have not been directly demonstrated. In this study, using a novel in situ detection system, we show that neurofibrillary tangles and senile plaques are major sites for catalytic redox reactivity. Pretreatment with deferoxamine or diethylenetriaminepentaacetic acid abolishes the ability of the lesions to catalyze the H2O2-dependent oxidation of 3,3'-diaminobenzidine (DAB), strongly suggesting the involvement of associated transition metal ions. Indeed, following chelated removal of metals, incubation with iron or copper salts reestablished lesion-dependent catalytic redox reactivity. Although DAB oxidation can also detect peroxidase activity, this was inactivated by H2O2 pretreatment before use of DAB, as shown by a specific peroxidase detection method. Model studies confirmed the ability of certain copper and iron coordination complexes to catalyze the H2O2-dependent oxidation of DAB. Also, the microtubule-associated protein tau, as an in vitro model for proteins relevant to AD pathology, was found capable of adventitious binding of copper and iron in a redox-competent manner. Our findings suggest that neurofibrillary tangles and senile plaques contain redox-active transition metals and may thereby exert prooxidant or possibly antioxidant activities, depending on the balance among cellular reductants and oxidants in the local microenvironment.
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PMID:In situ oxidative catalysis by neurofibrillary tangles and senile plaques in Alzheimer's disease: a central role for bound transition metals. 1061 29

Amplification with catalyzed reporter deposition (CARD) greatly enhances peroxidase signals, which has been utilized to amplify immunohistochemical labelings including fluorochromes. Here we describe a strategy to amplify each of two immunofluorescent signals without crosstalk on double-stained histological sections from human autopsied brains with Alzheimer's disease (AD). One of the two primary antibodies (anti-Abeta or anti-PHF-tau) was probed by a species-specific secondary antibody conjugated with horseradish peroxidase (HRP), which was visualized by FITC-labeled tyramide. After inactivation of HRP, the other primary antibody was probed by another species-specific secondary antibody conjugated with HRP. Amplification with biotinylated tyramide was followed by streptavidin-conjugated Cy-5, which specifically labeled the latter epitope. It was found that Abeta and PHF-tau were localized to senile plaques and neurofibrillary tangles (NFTs), respectively, which verified lack of crosstalk on the double-stained section. Localization of ubiquitin and PHF-tau was looked for at higher magnification in NFT-bearing neurons. Although these two epitopes were colocalized in some neurons, ubiquitin was not always present in PHF-tau positive NFTs. Discrepancy between PFH-tau and ubiquitin, verified inter- and intracellularly, may represent different stages of NFT formation. This is the first report of successful CARD amplification of two different fluorescent signals on double-labeling immunohistochemistry, which is now proved to be powerful in detecting epitopes in relation to AD-related lesions. Improved intensity over tenfold of the two fluorescent signals without crosstalk will expand the application of the multilabeling method with fluorochromes.
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PMID:Dual enhancement of double immunofluorescent signals by CARD: participation of ubiquitin during formation of neurofibrillary tangles. 1120 5

The senescence-accelerated strains of mice (SAMP) are well-characterized animal models of senescence. Senescence may be related to enhanced production or defective control of reactive oxygen species, which lead to neuronal damage. Therefore, the activity of various oxidative-stress related enzymes was determined in the cortex of 5 months-old senescence-accelerated mice prone-8 (SAMP-8) of both sexes and compared with senescence-accelerated mice-resistant-1 (SAMR-1). Glutathione reductase and peroxidase activities in SAMP-8 male mice were lower than in male SAMR-1, and a decreased catalase activity was found in both male and female SAMP-8 mice, which correlates with the lower catalase expression found by Western blotting. Nissl staining showed marked loss of neuronal cells in the cerebral cortex of five month-old SAMP-8 mice. SAMP-8 mice also had marked astrogliosis and microgliosis. We also found an increase in caspase-3 and calpain activity in the cortex. In addition, we observed morphological changes in the immunostaining of tau protein in SAMP-8, indicative of a loss of their structural function. Altogether, these results show that, at as early as 5 months of age, SAMP-8 mice have cytological and molecular alterations indicative of neurodegeneration in the cerebral cortex and suggestive of altered control of the production of oxidative species and hyper-activation of calcium-dependent enzymes.
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PMID:Changes in oxidative stress parameters and neurodegeneration markers in the brain of the senescence-accelerated mice SAMP-8. 1654 9


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