1,720,961 research outputs found
In vivo confocal reflectance microscopy for the characterization of melanocytic nests and correlation with dermoscopy and histology
No full textReflectance-mode confocal microscopy for the in vivo characterization of pagetoid melanocytosis in melanomas and nevi
No full textPagetoid infiltration of the epidermis by melanocytes is a relevant criterion for the histologic diagnosis of melanoma, although sporadically observable in benign lesions. Since in vivo reflectance-mode confocal microscopy enables the visualization of superficial layers at cellular-level resolution, the different aspects and the diagnostic significance of epidermal alterations and pagetoid cell infiltration were investigated on 84 benign and malignant melanocytic lesions by confocal microscopy and compared with histopathology. The observation of a disarranged pattern in superficial layers appeared characteristic for malignant lesions. In vivo identification of pagetoid cells, clearly present in the majority of melanomas and in a few benign lesions, seemed useful for melanoma diagnosis. An excellent concordance between confocal microscopy and histopathology was achieved. Moreover, identification of some characteristic features by confocal microscopy, such as large and numerous closely arranged cells extended to the stratum corneum, was strongly correlated with malignancy. In conclusion, confocal microscopy enabled a very good identification of melanocytes spreading upward in a pagetoid fashion in melanocytic lesions. Thus, when pagetoid melanocytosis is observable by means of confocal microscopy, melanoma diagnosis should be considered, whereas it cannot be excluded in the absence of pagetoid cells, lacking in at least 10% of malignant lesions
Expression of p27(kip1) in basal cell carcinomas and trichoepitheliomas
No full textImmunohistochemical analysis was used to evaluate p27(kip1) expression in normal hair follicles and in a series of 39 basal cell carcinomas (BCC) (13 of superficial type, 7 infiltrating, 7 morphea-like, 12 nodular) and 20 trichoepitheliomas (TE) (9 of classic type, 9 immature, 2 desmoplastic). The labeling index (LI) was derived semi automatically by means of a computer-assisted cellular image analyzer, and statistical analysis was carried out using the Student t test. A positive reaction for p27(kip1) was detected in the hair germ papillae, in supramatrical cells, and in the inner pilar sheath, whereas matrical cells and the outer pilar sheath were negative. All BCC and TE cases showed a positive immunoreaction for p27(kip1), but the staining pattern was different in the two groups of lesions, being patchy with focal peripheral accentuation in TE and more diffusely dispersed in BCC. The quantitative study showed lower p27(kip1) expression in BCC (LI = 27.51 +/- 12.55) than in TE (LI 45.27 +/- 20.27) (P < 0.0001). Statistically significant differences were also observed between TE subgroups and nodular or infiltrating BCC subtypes. The Occurrence of a wide overlap of LI values hampers the practical application of a p27(kip1) LI it, the differential diagnosis between BCC and TE in difficult cases, however
Spitz nevus is relatively frequent in adults - A clinico-pathologic study of 247 cases related to patient's age
No full textSpitz nevus is a clinico-pathologic entity that can cause diagnostic concern, particularly in adults. Many studies have been performed to establish reliable histologic criteria, in the attempt to differentiate this lesion from melanoma. A series of 247 Spitz nevi, 6 of which were formerly classified as melanomas, were reviewed for clinical and histopathological parameters. Patients older than 20 comprised 66% of cases, with a predominance of women. The lower extremity was more affected in females of any age, whereas the trunk was more frequently involved in men over 40. Histopathologic examination showed the following differences among Spitz nevi related to age: acanthosis, parakeratosis, pagetoid infiltration, and Kamino bodies were more frequent in young people, whereas multinucleated melanocytes were more frequent in adults. The latter also had lesions that were less pigmented, with less maturation and more desmoplasia. At a mean follow-up of 94 months (range 52-172), recurrence at the site of biopsy or metastases were absent. In our study, a greater proportion of Spitz nevi occurred in adults than in previous series. Moreover, the relative incidence of Spitz nevus compared with melanoma in our population was higher than in other studies. Histopathologic criteria elaborated to diagnose Spitz nevus, applied to our cases, appeared reliable, allowing a correct diagnosis, even in adults
Microscopic in vivo description of cellular architecture of dermoscopic pigment network in nevi and melanomas
No full textObjective: To characterize the microscopic aspects of the dermoscopic pigment network in vivo, by means of confocal scanning laser microscopy. Design: Confocal imaging was performed on melanocytic lesions characterized by pigment network at dermoscopy. Some confocal architectural and cytologic features, as observed at the dermoepidermal junction, were morphologically described and quantified by means of a dedicated program. Setting: University medical department. Study Population: We studied confocal images of 15 melanomas, 15 dermoscopic atypical nevi, and 15 common nevi. Main Outcome Measures: Features referring to aspect, size, regularity, homogeneity, and infiltration of dermal papillae and to cellular size, regularity, and atypia were described by 2 observers on confocal images. Mean dermal papillary diameter, mean cell area, and shape irregularity were quantified by drawing papillae and cell contours on confocal images and measured with the use of a computer program. Results: Pigment network in melanomas consisted of large basal cells that circumscribed small to medium-sized dermal papillae with marked cellular atypia, sometimes infiltrating dermal papillae. On the other hand, common acquired nevi were characterized by lack of atypical cells and edged dermal papillae. Atypical nevi presented intermediate characteristics between clearly benign and malignant lesions. Conclusion: Cellular atypia was the most sensitive feature for melanoma diagnosis, whereas the presence of nucleated cells infiltrating dermal papillae was the most specific one
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
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
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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