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A Bianchetti

Publications and source records attributed to A Bianchetti.

At least 19 recordsLinked to original sources
PubMed1996

Disorders of visual and spatial perception in the early stage of Alzheimer's disease.

A battery of visual and spatial perception tests (VOSP) has been administered to a sample of 25 mild Alzheimer's disease (AD) patients and 25 age- and education-matched controls in order to assess visuospatial skills in the early phase of the disease. Among visual object perception tests, AD patients were impaired only in the task where they had to name the stimulus (Silhouettes task). The score in this task significantly correlated with the Boston Naming Test score (r = .73; p < 0.0001). The performance on the Object decision task (which does not require naming), figure-ground analysis, and identification of degraded stimuli was unimpaired. Similarly there were no significant differences for any of the spatial perception tests. The results showing that the performances on most measures of visual and spatial perception is unimpaired, indicate that the "early" perceptual processes, as well as the access to structural knowledge, are not defective in early AD. On the other hand, AD patients are impaired at the level of semantic access and name retrieval. The finding of an highly significant correlation among tests requiring visual access to structural and semantic knowledge suggests that a rigid separation between perceptual and semantic mechanisms may be unwarranted.

Aged↗
PubMed1996

Defective protein kinase C alpha leads to impaired secretion of soluble beta-amyloid precursor protein from Alzheimer's disease fibroblasts.

The present study shows that cultured fibroblasts from sporadic AD patients present: a) reduced (-30%) cytosolic protein kinase C (PKC) activity; b) increased KD of phorbol ester binding (+94%) in cytosolic fractions; c) reduced (-30%) soluble protein kinase C alpha immunoreactivity; d) lower (-27.5%) basal soluble APP secretion and e) reduced soluble APP secretion in response to low phorbol ester concentrations (over threefold difference using 9 nM phorbol-12,13-dibutyrate-PdBu). Since the PKC-stimulated secretion of APP leads to the cleavage of the precursor within the amyloidogenic beta-A4 fragment, the reduced PKC activity in AD patients may lead to accumulation of potentially amyloidogenic or toxic APP fragments. A defect in the secretion of soluble amyloid beta-protein precursor is indeed suggested by literature data on familial AD fibroblasts as well as by the reported results.

Alzheimer Disease↗
PubMed1996

The Mini-Mental State Examination in Alzheimer's disease and multi-infarct dementia.

The aim of this study was to compare the performances on each item of the Mini-Mental State Examination (MMSE) of patients with Alzheimer's disease (AD) and multi-infarct dementia (MID). In order to identify the items that could better distinguish the two groups of patients, 70 AD and 31 MID patients matched for disease severity, age, and education were evaluated. The scores of the 101 patients on each of the MMSE items were entered into a principal component factor analysis using varimax rotation, and two main components were derived. Component 1 was probably representative of recently acquired information, whereas component 2 represented educational level. A score summing the items that loaded on component 1 and the recall item was calculated to generate a measure of episodic memory. Performing analysis of variance and covarying for age and education revealed that this score was statistically different in the two groups, with AD patients having lower values. The data suggest that the MMSE may demonstrate a pattern of impairment of memory that differs between AD and MID. Possible explanations of this finding should take into account the different neuroanatomical impairments and the different degrees of motivation, due to depression or attentional deficits, toward external stimuli.

Aged↗
PubMed1996

Dementia care.

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Aged↗
PubMed1996

Magnetic resonance and single-photon emission tomography findings in a pair of twins discordant for Alzheimer's disease.

The value of functional and morphological neuroimaging in the early diagnosis of Alzheimer's disease (AD) is still debated. Described here are cerebral perfusion and linear measures of medial temporal lobe atrophy in 2 monozygotic twins discordant for AD who were investigated with technetium 99m-hexamethylpropy-leneamineoxime single-photon emission tomography (SPET) and magnetic resonance (MR) imaging. Both showed pathological cortical perfusion findings on SPET, while medical temporal lobe atrophy was present only in the affected twin. MR measures of medial temporal lobe atrophy have greater agreement with clinical data than do SPET measures of cerebral perfusion. Evaluation of atrophy may be useful in the early diagnosis of AD.

Activities of Daily Living↗
PubMed1996

Executive dysfunction in early Alzheimer's disease.

Twenty five patients with probable mild Alzheimer's disease were assessed for deficits in executive functioning and the impact of these deficits on performance in other neuropsychological domains. The Wisconsin card sorting test, the release from proactive interference paradigm, the verbal fluency test, and the Stroop test were adopted to classify patients with (AD+) and without (AD-) executive deficits. Seven of the patients showed an impairment in executive function (AD+), defined as a performance below the cut off score in at least two of these tests. There were no significant differences in clinical assessments, demographic features, or other cognitive functions between patients. Executive dysfunction may be an early additional feature in a subgroup of patients with mild Alzheimer's disease. Impairment on frontal lobe tests does not seem to be related to the severity or duration of disease, or to a different pattern of impairment in other cognitive domains.

Aged↗
PubMed1996

Brain atrophy in frontotemporal dementia.

OBJECTIVES: To evaluate the pattern of regional brain atrophy in patients with frontotemporal dementia by comparing it with that in patients with Alzheimer's disease and normal controls. METHODS: Fourteen patients with frontotemporal dementia, 13 with moderate, and 33 with mild Alzheimer's disease, and 31 controls were studied. Atrophy was evaluated with linear measures in the anterior brain, medial temporal lobe, and hippocampal formation regions using MRI. RESULTS: Patients with frontotemporal dementia had greater atrophy in the anterior brain regions than patients with Alzheimer's disease or controls. Atrophy of the hippocampal formation, which best discriminates Alzheimer's disease from controls, was present also in patients with frontotemporal dementia. By contrast, atrophy of the medial temporal lobe, which is also present in Alzheimer's disease, was absent in frontotemporal dementia. CONCLUSION: A pattern of atrophy in the frontal lobes and hippocampal formation with sparing of the medial temporal lobe might be distinctive of frontotemporal dementia. Hippocampal involvement might not be specific for Alzheimer's disease and specific patterns of atrophy might be distinctive of some forms of degenerative dementia.

Aged↗
PubMed1996

Risk of mortality and institutionalization in demented patients with delusions.

Delusions are a common symptom during the course of dementia. Despite their clinical relevance, however, it is still unclear whether they are of prognostic value. This longitudinal study involving, at baseline, 99 demented Alzheimer disease (AD) and multi-infarct dementia (MID) patients, investigates the risk of mortality and institutionalization at 2 years after discharge from a dementia unit in patients with and without delusions at baseline. Results indicate that the presence of delusions is a significant predictor of future institutionalization (odds ratio 3.6, confidence interval 1.3-9.6), even when confounding factors such as age, educational level, and severity of cognitive and functional impairment are statistically controlled. No significant impact on survival was found.

Aged↗
PubMed1996

Fibroblasts of patients affected by Down's syndrome oversecrete amyloid precursor protein and are hyporesponsive to protein kinase C stimulation.

The present study investigates the ability of the pharmacologic activation of protein kinase C (PKC) to modulate amyloid precursor protein (APP) secretion in human skin fibroblasts from patients affected by Down's syndrome (DS). We assessed DS subjects at the Hospital Institute of Sospiro, Cremona, and at the Alzheimer's Disease Unit of the Sacred Heart Hospital in Brescia, and we subdivided them into nondemented (NDS) and demented (DDS) patients. All DS patients were trisomy 21 karyotype. DS fibroblasts had an increased content of APP immunoreactive material as revealed by immunocytochemistry analysis. The basal secretion of soluble APP was higher (+94.6%) in Down's cells with respect to controls. The observation on the fibroblasts prepared from DS is consistent with these patients' possessing an extra copy of the APP gene (mapped on chromosome 21) leading to increased APP expression. Phorbol-12,13-dibutyrate (PdBu, 9 to 150 nM) treatment promoted a dose-dependent increase of secreted APP in the conditioned medium of control fibroblasts. The peak response (+102.2%) was attained using 150 nM PdBu. In Down's fibroblasts, PdBu stimulated APP secretion already maximally at low concentrations (9 nM), but the peak response, due to the higher basal release, was lower on a percentage basis (+16.4%) than in control fibroblasts. The results indicate that in Down's fibroblasts the mechanisms controlling APP release are at least quantitatively altered. In addition, these results suggest caution when using information obtained from Down's patients to model Alzheimer's disease biochemical defects.

Adult↗
PubMed1996

Apolipoprotein E.

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Apolipoproteins E↗
PubMed1996

Linear measures of atrophy in mild Alzheimer disease.

PURPOSE: To assess the sensitivity of linear measures of brain atrophy in the diagnosis of Alzheimer disease (AD) in the early stages. METHODS: Linear measures of regional frontal (Bifrontal index, interhemispheric fissure width), medial temporal lobe (interuncal distance, minimum thickness of the medial temporal lobe), and hippocampal (hippocampal height, width of the choroid fissure, width of the temporal horn) atrophy were made on magnified MR images obtained in 46 patients with AD (33 with mild severity and 13 with moderate severity) and in 31 control subjects. Gaussian modeling was used to compute sensitivity with specificity set at 95%. Discriminant analysis was used to identify measures independently contributing to the ability to discriminate AD patients from control subjects. RESULTS: The measure with the best sensitivity in discriminating AD patients from control subjects was the width of the temporal horn. A compound measure of width of the temporal horn, width of the choroid fissure, height of the hippocampus, and interuncal distance could discriminate patients with mild AD from control subjects with 86% sensitivity. Cross validation in patients with moderate AD confirmed the usefulness of the model (81% sensitivity). Measures of hippocampal atrophy alone could discriminate patients with mild AD from control subjects with 83% sensitivity; in patients with moderate AD, cross validation produced 87% sensitivity. CONCLUSIONS: Linear measures of hippocampal atrophy can be a useful adjunct in the routine diagnosis of AD, even in its early stages.

Aged↗
PubMed1995

Defective phorbol ester-stimulated secretion of beta-amyloid precursor protein from Alzheimer's disease fibroblasts.

The present study shows that cultured fibroblasts from sporadic Alzheimer's disease patients are deficient in protein kinase C-regulated secretion of amyloid precursor protein. In particular, Alzheimer fibroblasts show a reduced basal secretion and a reduced response at low concentrations of phorbol-12,13-dibutyrate, with an EC50 twofold higher than control fibroblasts. Furthermore, we observed that such defective regulation of the amyloid precursor secretion can possibly be correlated to a specific defect in protein kinase C alpha in fibroblasts from Alzheimer patients.

Aged↗