Pick's complex and FTDP-17

This essay advances the thesis with a review of the evidence that Pick's disease, frontotemporal dementia, primary progressive aphasia, corticobasal degeneration, and progressive supranuclear palsy should be regarded as a clinically and biologically cohesive spectrum. The historically correct eponymic term Pick's complex, for both the clinical and pathological varieties is preferred. The discovery of tau mutations in frontotemporal dementia and parkinsonism linked to specific mutations in chromosome 17 and their resemblance to the sporadic cases validates the concept of Pick's complex. There are recently discovered overlaps between the three-repeat and four-repeat tauopathies, and the tau-negative varieties with or without motor neuron disease-type inclusions may be deficient in normal tau, therefore may be tauopathies also. Although clinical, pathological, and biochemical distinctions continue to be important, integration promises to be productive in this family of not so rare diseases.

Aluminum neurotoxicity: an experimental approach to the induction of neurofilamentous inclusions

Acute or chronic aluminum neurotoxicity experiments in the rabbit suggest that aluminum can induce phosphorylation of neurofilamentous proteins. This may result in abnormal resistance to degradation or transport of neurofilament protein and so to the accumulation of neurofilaments in abnormal cells. The possible importance of this process in ALS is considered in relation to the neurofilamentous abnormalities characteristic of intraneuronal inclusions in ALS and in other neurodegenerative disorders.

Neurofibrillary tangles of Guamanian amyotrophic lateral sclerosis, parkinsonism-dementia and neurologically normal Guamanians contain a 4- to 4.5-kilodalton protein which is immunoreactive to anti-amyloid beta/A4-protein antibodies

Neurofibrillary tangles (NFT), one of the neurodegenerative features of Alzheimer's disease, Down's syndrome and normal aging, is a constant, widespread neuropathological finding in Guamanian amyotrophic lateral sclerosis (ALS), parkinsonism-dementia (PD) and in neurologically normal Guamanians, dying of causes other than ALS and PD. NFT in brain tissue sections of patients with Guamanian ALS and PD were immunoreactive to antibodies directed against a 43-amino acid synthetic peptide homologous to amyloid beta/A4-protein (anti-SP43) associated with Alzheimer's disease. NFT extracted from frozen brain tissues of Guamanian patients with ALS and PD and from tissues of neurologically normal Guamanians were congophilic and birefringent. By negative-stain electron microscopy, NFT preparations contained bundles and/or isolated single, straight, unpaired filaments in Guamanian ALS and occasionally pairing of filaments in neurologically normal Guamanians, measuring 5-20 nm in diameter. Formic acid digestion of NFT preparations, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and size-exclusion high-pressure liquid chromatography, showed a protein with an apparent molecular mass of 4- to 4.5-kDa, which by Western blot analysis was immunoreactive to anti-SP43. Immunoabsorption of purified NFT or SP43 with anti-SP43 abolished immunostaining. Our study corroborate previous data that amyloid beta/A4-protein is present in NFT in Guamanian PD. Furthermore, our data indicate that amyloid beta/A4-protein is present in NFT in brain tissues of patients with Guamanian ALS and in neurologically normal Guamanians, suggesting a common mechanism of amyloidogenesis with NFT formation in Alzheimer's disease and normal brain aging.

Models of environmentally induced neurological disease: epidemiology and etiology of amyotrophic lateral sclerosis and parkinsonism-dementia in the Western Pacific

Amyotrophic lateral sclerosis (ALS) on Guam previously attained incidence rates 50 to 100 times that of the continental United States and Europe and accounted for one in five deaths among Chamorros over age 25. A second neurological disorder in high incidence, parkinsonism-dementia (PD), and the early appearance in those populations of neurofibrillary tangles such as are seen in Alzheimer's disease and normal ageing have also been noted. Incidence and mortality rates of both diseases have declined dramatically during the past 30 years, and today, the risk of developing either disease among Guamanian Chamorros is only several times higher than in non-Guamanian populations. The decline is most likely a consequence of increased acculturation over the past three decades, with a concomitant decrease in isolation, changes in dietary habits and local water supplies, and much less dependence on locally grown foodstuffs. Similar declines are evident in the remaining two Pacific foci of high- incidence ALS, namely the Kii Peninsula focus in Japan and southern West New Guinea where western contact and introduction of new foodstuffs have occurred.The accumulating epidemiological, genetic and environmental evidence, as well as the development of new and promising experimental animal models, support the hypothesis that a basic metabolic defect, provoked by chronic nutritional deficiencies of calcium, lead to increased intestinal absorption of toxic metals and the co-deposition of calcium, aluminium and silicon in neurons of patients with ALS and PD. This elemental deposition is thought to result in aberrant microtubule assembly and/or abnormal post-translational modification of the amyloid precursor protein leading to widespread formation of neurofibrillary tangles, the hallmark pathological features in these disorders. The naturalistic paradigms of these foci in the Western Pacific have provided insights to understanding not only ALS and PD but other neurological disorders, such as classical ALS, Parkinson's disease, Alzheimer's disease and early neuronal ageing.