| neurofibrillary degeneration | Formation of coarse, argentophilic, intracytoplasmic fibres, often in complex tangles within intracranial nerve cells that are undergoing aging. See: Alzheimer's disease. (05 Mar 2000) |
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| neurofibrillary tangle | <cell biology> Accumulation of twisted protein fragments inside nerve cells. Neurofibrillary tangles are one of the characteristic structural abnormalities found in the brains of patients with Alzheimer's disease patients. Upon autopsy, the presence of neuritic plaquesand neurofibrillary tangles is used to positively diagnose Alzheimer's disease. (22 May 1997) |
| neurofibrillary tangles | Abnormal structures located in various parts of the brain and composed of dense arrays of paired helical filaments (neurofilaments and microtubules). These double helical stacks of transverse subunits are twisted into left-handed ribbon-like filaments that likely incorporate the following proteins: 1) the intermediate filaments: medium- and high-molecular-weight neurofilaments; 2) the microtubule-associated proteins map-2 and tau; 3) actin; and 4) ubiquitin. As one of the hallmarks of alzheimer disease, the neurofibrillary tangles eventually occupy the whole of the cytoplasm in certain classes of cell in the neocortex, hippocampus, brainstem, and diencephalon. The number of these tangles, as seen in post mortem histology, correlates with the degree of dementia during life. Some studies suggest that tangle antigens leak into the systemic circulation both in the course of normal aging and in cases of alzheimer disease. (12 Dec 1998) |