1,720,970 research outputs found
Classical and cellular (atypical) congenital mesoblastic nephroma: a clinicopathologic, ultrastructural, immunohistochemical, and flow cytometric study.
No full textSixteen cases of congenital mesoblastic nephroma (CMN) were studied. The tumors showed variable patterns of growth, degrees of cellularity, and mitotic activity. Six tumors had the classical pattern of CMN, seven were of the cellular or atypical variant and three showed combined features. The mean ages at presentation were 16 days, 5.3 months, and 2.3 months, respectively. Average size and weight were 5.1 cm and 94 g for classical CMN, 9.1 cm and 620 g for cellular CMN and 10.5 cm and 150 g for combined tumors. Cyst formation, hemorrhage and necrosis were confined to cellular CMNs and to cellular areas of combined CMNs. Mitotic activity ranged from 0 to 1/10 high-power fields (HPFs) in classical tumors to 25 to 30/10 HPFs in cellular tumors. Clear cell sarcoma-like areas were observed in three neoplasms. In ten cases there was invasion of perirenal fat; in one case each, invasion of the psoas muscle, renal vein wall, and renal vein lumen was observed. Ultrastructural and immunohistochemical studies showed features consistent with myofibroblastic differentiation. Flow cytometric analysis revealed euploidy in one classic CMN, one cellular CMN and in classic areas of a combined CMN; cellular areas of the latter tumor were aneuploid. All patients with follow-up were alive without evidence of disease after a mean period of 5 years following nephrectomy alone. No correlation was observed between the pathologic features assessed and the biologic behavior of these neoplasms
Primary bronchopulmonary fibrosarcoma of childhood and adolescence: reassessment of a low-grade malignancy. Clinicopathologic study of five cases and review of the literature.
No full textIn children, primary tumors of the lung constitute a unique subset of quasineoplastic and unequivocally neoplastic lesions whose benign or malignant potential is not always predictable on the basis of morphologic findings. One such neoplasm in the latter category is the primary bronchopulmonary fibrosarcoma (PBPF). This clinicopathologic, ultrastructural, and immunohistochemical study documents our experience with five PBPFs in newborns and children up to 11 years of age at diagnosis. The tumors were either endobronchial or intraparenchymal in location. A uniform population of interlacing bundles and sheets of densely arranged spindle cells with variable mitotic activity was observed microscopically in each case. Ultrastructurally, the cells had the features of fibroblasts and vimentin was the only immunohistochemical marker identified. Despite the disturbing pathologic findings, the four children with more than 1 year of follow-up have survived well 4 to 9 years after surgical resection. Our results are compared with the 21 cases of PBPF reported in the literature and the differential diagnosis is discussed
Inflammatory myofibroblastic tumor (plasma cell granuloma). Clinicopathologic study of 20 cases with immunohistochemical and ultrastructural observations.
No full textTwenty cases of inflammatory myofibroblastic tumor (IMT) were studied; 19 involved the lung and 1 the esophagus only. The patients' ages ranged from 3 to 72 years. There were 9 males and 11 females. Involvement of a bronchus was seen in one case and of mediastinal structures in four. Chest pain and dyspnea were common symptoms; eight patients were asymptomatic. Seven patients underwent lobectomy, 12 local excision, and 1 biopsy alone. The lesions were nonencapsulated and ranged from 1.2 to 15 cm. Various proportions of plasma cells, histiocytes, and spindle cells were observed; the latter corresponded ultrastructurally to fibroblasts and myofibroblasts, were immunoreactive for vimentin and actin and focally for desmin, and were negative for epithelial markers. Plasma cells were polyclonal for light chains. One patient had two recurrences, and in one case a large pleural IMT was found eight years after the excision of a similar lesion in the lung. All patients with follow-up (ten) were well as long as ten years after the diagnosis (average, 3.7 years)
Prune belly syndrome: clinicopathologic study of 29 cases.
No full textThe clinical course and the pathologic features of 29 patients with the prune belly syndrome (PBS) are reviewed. There were 26 males and 3 females. In addition to the classical triad of deficient abdominal musculature, urinary tract abnormalities, and cryptorchidism, a broader spectrum of other defects was found including musculoskeletal (58\%) and gastrointestinal (31\%) abnormalities. Genital anomalies were present in all three female patients. Many of these defects may be inapparent at birth, but are the cause of morbidity and mortality later in life. Severe urinary tract maldevelopment and pulmonary hypoplasia as part of the oligohydramnios syndrome was the most common cause of perinatal deaths. In these patients, major portions of the renal parenchyma were dysplastic, but in survivors, renal dysplasia, when present, was minor by comparison, and affected less than 1/3 of the parenchyma. Although several questions remain unanswered, we believe that the PBS results from the effect of one or more teratogenic agents on the somatic mesoderm, producing inappropriate mesenchymal development and inadequate mesenchymal-epithelial interactions that lead to abnormal development and dilatation of some of its derivatives (abdominal muscles, ureter, bladder, prostate, urethra, and gubernaculum). Although abnormalities in derivatives of the intermediate mesoderm (kidney) may also be produced by the injurious agent(s), they are more likely a result of urinary obstruction. Abnormalities in other organs and systems are the consequence of oligohydramnios
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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