D. Munoz‐Garcia

Bio: D. Munoz‐Garcia is an academic researcher from Kingston General Hospital. The author has contributed to research in topics: Pick's disease & Cytoplasmic inclusion. The author has an hindex of 1, co-authored 1 publications receiving 194 citations.

Classic and generalized variants of Pick's disease: A clinicopathological, ultrastructural, and immunocytochemical comparative study

Abstract: Six sporadic cases of dementia with lobar atrophy and neuronal cytoplasmic inclusions (Pick's disease) could be separated into two groups on the basis of the involvement of subcortical structures, the distribution and the histochemical, immunochemical, and ultrastructural characteristics of the inclusions, and possibly the age at onset. The first group (classic) was characterized by predominantly cortical atrophy and the presence in the hippocampus and neocortex of argyrophilic cytoplasmic inclusion bodies that reacted with a monoclonal antibody against neurofilament proteins and antitubulin antisera. Ultrastructurally the bodies were composed of straight fibrils of variable diameter, averaging 15 nm, and long-period constricted fibrils. The second group (generalized) showed subcortical as well as cortical atrophy. Cortical and subcortical cytoplasmic inclusions contained RNA and stained poorly with silver and antibodies against neurofilaments and microtubules. Ultrastructurally the straight fibrils composing the bodies were coated with granular material, presumed to be derived from ribosomes. The generalized cases occurred in younger patients than did the classic cases in this series.

TDP-43 and FUS in amyotrophic lateral sclerosis and frontotemporal dementia

Abstract: Abnormal intracellular protein aggregates comprise a key characteristic in most neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The seminal discoveries of accumulation of TDP-43 in most cases of ALS and the most frequent form of FTD, frontotemporal lobar degeneration with ubiquitinated inclusions, followed by identification of FUS as the novel pathological protein in a small subset of patients with ALS and various FTD subtypes provide clear evidence that these disorders are related. The creation of a novel molecular classification of ALS and FTD based on the identity of the predominant protein abnormality has, therefore, been possible. The striking functional and structural similarities of TDP-43 and FUS, which are both DNA/RNA binding proteins, imply that abnormal RNA metabolism is a pivotal event, but the mechanisms leading to TDP-43 and FUS accumulation and the resulting neurodegeneration are currently unknown. Nonetheless, TDP-43 and FUS are promising candidates for the development of novel biomarker assays and targeted therapies.

ALS-associated fused in sarcoma (FUS) mutations disrupt Transportin-mediated nuclear import

Abstract: Mutations in fused in sarcoma (FUS) are a cause of familial amyotrophic lateral sclerosis (fALS). Patients carrying point mutations in the C-terminus of FUS show neuronal cytoplasmic FUS-positive inclusions, whereas in healthy controls, FUS is predominantly nuclear. Cytoplasmic FUS inclusions have also been identified in a subset of frontotemporal lobar degeneration (FTLD-FUS). We show that a non-classical PY nuclear localization signal (NLS) in the C-terminus of FUS is necessary for nuclear import. The majority of fALS-associated mutations occur within the NLS and impair nuclear import to a degree that correlates with the age of disease onset. This presents the first case of disease-causing mutations within a PY-NLS. Nuclear import of FUS is dependent on Transportin, and interference with this transport pathway leads to cytoplasmic redistribution and recruitment of FUS into stress granules. Moreover, proteins known to be stress granule markers co-deposit with inclusions in fALS and FTLD-FUS patients, implicating stress granule formation in the pathogenesis of these diseases. We propose that two pathological hits, namely nuclear import defects and cellular stress, are involved in the pathogenesis of FUS-opathies.

Ubiquitin is a common factor in intermediate filament inclusion bodies of diverse type in man, including those of Parkinson's disease, Pick's disease, and Alzheimer's disease, as well as Rosenthal fibres in cerebellar astrocytomas, cytoplasmic bodies in muscle, and mallory bodies in alcoholic liver disease.

Abstract: Polyclonal antibodies were raised which have a high affinity for conjugated ubiquitin. Immunocytochemistry was performed on paraffin sections of tissues showing well-characterized inclusion bodies. Ubiquitin was found as a component of the intermediate filament inclusion bodies characteristic of several major diseases including Lewy bodies of Parkinson's disease, Pick bodies of Pick's disease, Mallory bodies of alcoholic liver disease, cytoplasmic bodies of a specific myopathy, and Rosenthal fibres within astrocytes. Ubiquitin was also present in the three histological lesions characteristic of Alzheimer's disease. These observations suggest a fundamental role for ubiquitin in the formation of intermediate filament inclusion bodies in man, and have implications regarding the pathogenesis of these important diseases.

Dementia of frontal lobe type.

Abstract: A significant proportion of patients with presenile dementia due to primary cerebral atrophy do not have Alzheimer's disease. One form of non-Alzheimer dementia may be designated as dementia of frontal lobe type (DFT), on the basis of a characteristic neuropsychological picture suggestive of frontal lobe disorder, confirmed by findings on single photon emission tomography. The case histories of seven patients exemplify the disorder: a presentation of social misconduct and personality change, unconcern and disinhibition, in the presence of physical well-being and few neurological signs. Assessment revealed economic and concrete speech with verbal stereotypes, variable memory impairment, and marked abnormalities on tasks sensitive to frontal lobe function. Visuo-spatial disorder was invariably absent. Comparisons of DFT and Alzheimer patients revealed qualitative differences in clinical presentation, neurological signs, profile of psychological disability, electroencephalography, single photon emission tomography and demography. DFT, which may represent forms of Pick's disease, may be more common than is often recognised.

Dementia lacking distinctive histologie features: A common non‐Alzheimer degenerative dementia

Abstract: From a series of 460 dementia patients referred to a regional brain bank, 14 (3%) patients had a pathologic diagnosis of primary degeneration of the brain involving multiple sites (frontoparietal cortex, striatum, medial thalamus, substantia nigra, and hypoglossal nucleus), with cell loss and astrocytosis. There were no neuronal inclusions and essentially no senile plaques. This entity, which we have termed “dementia lacking distinctive histology” (DLDH), presented with memory loss and personality changes, and led to death, usually within 2 to 7 years. Dysarthria and dysphagia were prominent in the later phases of the illness in most patients. The psychometric findings of some of the patients were consistent with a “frontal” lobe dementia. A few patients had prominent caudate atrophy on CT as well as neuropathologically. Eight of our patients had positive family histories for neurologic disease, mainly dementia. DLDH, in addition to Pick9s disease, is a major member of the frontal-lobe dementia group. In patients under age 70 years, the frontal lobe dementias represent an important diagnostic consideration.