1,721,026 research outputs found
La tragedia sulla scena. La tragedia greca in quanto spettacolo teatrale
Saggio sulla ricostruzione della messa in scena originaria di una tragedia antica
The intrinsic combinatorial organization and information theoretic content of a sequence are correlated to the DNA encoded nucleosome organization of eukaryotic genomes
Motivation: Thanks to research spanning nearly 30 years, two major models have emerged that account for nucleosome organization in chromatin: statistical and sequence specific. The first is based on elegant, easy to compute, closed-form mathematical formulas that make no assumptions of the physical and chemical properties of the underlying DNA sequence. Moreover, they need no training on the data for their computation. The latter is based on some sequence regularities but, as opposed to the statistical model, it lacks the same type of closed-form formulas that, in this case, should be based on the DNA sequence only. Results: We contribute to close this important methodological gap between the two models by providing three very simple formulas for the sequence specific one. They are all based on well-known formulas in Computer Science and Bioinformatics, and they give different quantifications of how complex a sequence is. In view of how remarkably well they perform, it is very surprising that measures of sequence complexity have not even been considered as candidates to close the mentioned gap. We provide experimental evidence that the intrinsic level of combinatorial organization and information-theoretic content of subsequences within a genome are strongly correlated to the level of DNA encoded nucleosome organization discovered by Kaplan et al. Our results establish an important connection between the intrinsic complexity of subsequences in a genome and the intrinsic, i.e. DNA encoded, nucleosome organization of eukaryotic genomes. It is a first step towards a mathematical characterization of this latter 'encoding'. Supplementary information: Supplementary data are available at Bioinformatics onlin
Unclassified pediatric renal stromal tumor overlapping with metanephric stromal tumor and solitary fibrous tumor with diffuse S-100 protein expression.
Metanephric stromal tumor (MST) is a rare pediatric neoplasm unique to the kidneys that is currently included in the spectrum of metanephric tumors, along with metanephric adenoma and adenofibroma. We herein report an unusual case of pediatric renal stromal tumor overlapping with MST and solitary fibrous tumor (SFT). Histologically, the tumor was composed of bland-looking spindle to stellate cells embedded in a fibro-sclerotic stroma that focally surrounded native entrapped renal tubules or blood vessels with abortive rings or collarettes. Alternating hypercellular and hypocellular areas and a focal hemangiopericytomatous-like vascular pattern imparted to the tumor a resemblance to SFT. Angiodysplasia of intratumoral arterioles was also observed, but juxtaglomerular cell hyperplasia was not a feature. Immunohistochemically, the neoplastic cells showed a polyphenotypic profile, including diffuse expression of vimentin and CD34, and focal immunoreactivity for alpha-smooth muscle actin, EMA, and CD99. However, the most striking finding was diffuse nuclear and cytoplasmic expression of S-100 protein. Although this protein has been reported to stain the heterologous glial and/or cartilaginous components that can be occasionally encountered in MST, this marker has not been previously reported in the fibroblastic component of MST. Pathologist should be aware of similar unusual unclassified tumors to avoid potential confusion with other benign or malignant S-100 protein-positive tumors
Idronefrosi del distretto inferiore in duplicità pieloureterale incompleta: presentazione di due casi.
Experimental substitution of thoracic oesophagus with interposed gastric tube, preserving L.E.S. functions. Clinical and histological findings in the follow-up
Going Beyond Counting First Authors in Author Co-citation Analysis
The 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
Pyloric atresia: a new operation to reconstruct the pyloric sphincter
BACKGROUND/PURPOSE:
The standard method of surgical correction of pyloric atresia "solid segment" type is a gastroduodenostomy that can in the long term cause bilious duodenogastric reflux. The authors report 2 cases of pyloric atresia in which the pyloric sphincter was reconstructed by a new technique of gastroduodenal mucosal advancement anastomosis.
METHODS:
Two premature babies with "solid segment"-type pyloric atresia, one with an associated junctional epidermolysis bullosa, underwent surgery for reconstruction of the pyloric sphincter. By a longitudinal incision of the atretic pylorus, the cul-de-sacs of gastric and duodenal mucosa were isolated in the respective gastric and duodenal sides, advanced into the opened pyloric canal, and sutured together using end-to-end anastomosis. The longitudinal pyloromyotomy then was closed above the reconstructed mucosal pyloric neocanal.
RESULTS:
The postoperative course was normal. At 7 years (patient 1) and 2 years (patient 2) after the operation, both are well, and no gastrointestinal disorders are present. Good competence of the pyloric sphincter has been confirmed by x-ray barium meal in both cases, and by HIDA technetium 99m hepatic scintiscan and esophagogastroduodenoscopy (EGD) with biopsy in patient 1.
CONCLUSIONS:
Our technique of surgical correction of pyloric atresia allows preservation of the pyloric sphincter, whose muscular layer, although hypoplastic, is present in these cases
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