1,721,003 research outputs found
Il popolamento a Coleoptera Chrysomelidae del massiccio del Gran Sasso: analisi zoogeografica ed autoecologica (Insecta).
No full textIs blood brain-derived neurotrophic factor a useful biomarker to monitor mild cognitive impairment patients?
No full textAvailability of reliable prognostic biomarkers that are also able to monitor preventive/therapeutic interventions in patients with mild cognitive impairment (MCI) is crucial. Cerebral brain-derived neurotrophic factor (BDNF) alterations were evidenced in Alzheimer's disease, but the value of blood BDNF in MCI is unclear, especially because of the incomplete/incorrect management of the numerous confounding factors unrelated to the disease. This study, applying a multidisciplinary methodological approach, aimed at clarifying whether blood BDNF can really mirror the cognitive symptoms of MCI, thus supporting the evaluation of clinical protocols' effectiveness as well as the definition of the conversion rate to dementia. Healthy elderly subjects (HE) and MCI patients were assessed for sociodemographic, neuropsychological, pharmacological, and lifestyle data, and plasma BDNF was measured (baseline); then, in the MCI cohort, the biomarker was tested in a comprehensive cognitive stimulation intervention (CS) as well as in a 2-year follow-up period. Plasma BDNF, cleansed from all the interfering factors, (1) did not discriminate HE and MCI patients; (2) in MCI patients reflected mood, social engagement, and subjective memory complaints but not cognition; (3) changed due to CS, although with no correlations to cognitive performances; and (4) predicted no functional deterioration. Our data indicate that the possible biased use of plasma BDNF in MCI is critically risky
Effect of a cognitive training program on the platelet app ratio in patients with alzheimer’s disease
Full text linkIn patients with Alzheimer’s disease (AD), synaptic plasticity seems to be involved in cognitive improvement induced by cognitive training. The platelet amyloid precursor protein (APP) ratio (APPr), i.e., the ratio between two APP isoforms, may be a useful peripheral biomarker to investigate synaptic plasticity pathways. This study evaluates the changes in neuropsychological/cognitive performance and APPr induced by cognitive training in AD patients participating in the “My Mind Project”. Neuropsychological/cognitive variables and APPr were evaluated in the trained group (n = 28) before a two-month experimental protocol, immediately after its termination at follow-up 1 (FU1), after 6 months at follow-up 2 (FU2), and after 24 months at follow-up 3 (FU3). The control group (n = 31) received general psychoeducational training for two months. Some memory and attention parameters were significantly improved in trained vs. control patients at FU1 and FU2 compared to baseline (∆ values). At FU3, APPr and Mini Mental State Examination (MMSE) scores decreased in trained patients. ∆ APPr correlated significantly with the ∆ scores of (i) MMSE at FU1, (ii) the prose memory test at FU2, and (iii) Instrumental Activities of Daily Living (IADL), the semantic word fluency test, Clinical Dementia Rating (CDR), and the attentive matrices test at FU3. Our data demonstrate that the platelet APPr correlates with key clinical variables, thereby proving that it may be a reliable biomarker of brain function in AD patients
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Biocomplexity and Fractality in the Search of Biomarkers of Aging and Pathology: Mitochondrial DNA Profiling of Parkinson’s Disease
Full text linkIncreasing evidence implicates mitochondrial dysfunction in the etiology of Parkinson’s
disease (PD). Mitochondrial DNA (mtDNA) mutations are considered a possible cause and this
mechanism might be shared with the aging process and with other age-related neurodegenerative
disorders such as Alzheimer’s disease (AD). We have recently proposed a computerized method for
mutated mtDNA characterization able to discriminate betweenADand aging. The present study deals
with mtDNA mutation-based profiling of PD. Peripheral blood mtDNA sequences from late-onset PD
patients and age-matched controls were analyzed and compared to the revised Cambridge Reference
Sequence (rCRS). The chaos game representation (CGR) method, modified to visualize heteroplasmic
mutations, was used to display fractal properties of mtDNA sequences and fractal lacunarity analysis
was applied to quantitatively characterize PD based on mtDNA mutations. Parameter , from the
hyperbola model function of our lacunarity method, was statistically dierent between PD and
control groups when comparing mtDNA sequence frames corresponding to GenBank np 5713-9713.
Our original method, based on CGR and lacunarity analysis, represents a useful tool to analyze
mtDNA mutations. Lacunarity parameter is able to characterize individual mutation profile of
mitochondrial genome and could represent a promising index to discriminate between PD and agin
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Early impairment of long-term depression in the perirhinal cortex of a mouse model of Alzheimer’s disease.
No full textTg2576 is one of the most widely used mouse transgenic line in Alzheimer’s disease (AD) research. It carries a double missense mutation on the amyloid precursor protein gene (APP), resulting in marked increases in b-amyloid (Ab) 1–40 and Ab1–42 in the plasma and brain by 3–5 months of age, decrease in spine density in the outer molecular layer of the dentate gyrus at 4
months, decline in long-term potentiation of synaptic transmission
in the dentate gyrus associated with impairment in contextual
fear conditioning by 5 months, and plaque deposition in
brain starting at 8 months. Visual recognition memory is seriously
impaired in patients in the early stages of AD. The perirhinal
cortex (Prh), a multimodal associative cortex of the
temporal lobe, is critically involved in this form of memory;
long-term depression of synaptic transmission (LTD) in this
cortical region is regarded as its cellular correlate. The present
work was aimed at evaluating if LTD in Prh of Tg2576 mice is
already compromised at 3 months of age. Field excitatory postsynaptic
potentials evoked by afferent pathways stimulation
were recorded in layer II/III of Prh in horizontal brain slices
obtained from 3 month old Tg2576 mice and littermate controls.
We found that a single train of 3000 pulses delivered at 5 Hz
induced LTD in slices from control mice, but not in those from
Tg2576 mice. This result is consistent with the early visual recognition
impairment observed in AD patients, and is particularly
interesting because no changes in synaptic plasticity have
previously been found so early in this transgenic line. Indeed,
one of the major goals in AD research is to characterize the
mechanisms leading to early functional impairments in order to improve diagnostic and therapeutic tools
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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