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Ependimoblastoma: caratteristiche neuroradiologiche di un raro tumore neuroectodermico
No full textINTRODUZIONE. L’ependimoblastoma è un raro tumore neuroectodermico maligno. Sebbene le caratteristiche cli- nico-patologiche siano ben conosciute e ampiamente ripor- tate, i reperti neuroradiologici non sono stati ancora defini- ti chiaramente. Ad oggi infatti, tramite ricerca e-PubMed, solo un caso è stato descritto dal punto di vista neuroradio- logico.
Riportiamo quindi un caso di ependimoblastoma cerebrale, esaminando gli aspetti neuroradiologici alla luce dei dati pubblicati in letteratura.
DESCRIZIONE DEL CASO. ll piccolo P.M. di 1 anno e 10 mesi è giunto alla nostra osservazione per una sintomatologia caratterizzata da apatia, inappetenza, calo ponderale di circa 1,5 kg seguita da vomito ed irritabilità.
In relazione ai sintomi di ipertensione endocranica venne richiesta una risonanza magnetica (RM) encefalica che dimostrava: voluminosa massa, ben delimitata, in sede fronto-temporo-parietale destra (circa 7 cm di diametro massimo), non chiaramente definibile se intra- o extra-ven- tricolare.
La lesione era caratterizzata da segnale disomogeneo: iso- ipointenso nelle sequenza T1-w, iperintenso nelle sequenze TR lungo (T2-w e FLAIR), nel cui contesto erano inoltre apprezzabili dei segni di sanguinamento recente e multiple zone necrotico-cistiche. La somministrazione di mezzo di contrasto determinava un’intensa impregnazione della componente solida della lesione.
Lo studio di diffusione (DWI) mostrava una marcata restri- zione della diffusione, in relazione ad aumento della cellu- larità, nella lesione rispetto al tessuto cerebrale normale.
Fin dal primo esame si notava una sottile impregnazione leptomeningea sul margine anteriore del passaggio ponto- mesencefalico.
Veniva pertanto sottoposto a due interventi chirurgici. Durante il primo, a causa della grave ipertensione endocra- nica, si verificava una profusa emorragia endocranica e si effettuava una asportazione parziale della massa; con il secondo intervento si eradicava completamente la massa tumorale, che risultava completamente intraventricolare. Il controllo neuroradiologico postchirurgico dimostrava gli esiti di intervento chirurgico, con escissione completa della massa, ma si rilevava disseminazione leptomeningea diffu- sa a livello del midollo spinale.
All’esame istologico la massa asportata risultava un epen- dimoblastoma (IV grado WHO).
DISCUSSIONE. Questi tumori originano dal cellule progeni- trici del neuroepitelio periventricolare che vanno incontro a differenziazione incompleta con aspetti sia di tipo gliale che ependimale a carattere immaturo. Sebbene dal punto di vista istologico l’ependimoblastoma sia chiaramente distinto dai PNET (tumori neuroectodermici indifferenzia- ti), le caratteristiche neuroradiologiche non mostrano una chiara distinzione. Una grande massa sovratentoriale, in stretto rapporto con le pareti ventricolari, chiaramente demarcata, con minimo edema perilesionele, e con impre- gnazione eterogenea dopo somministrazione di contrasto, in un bambino piccolo, dovrebbe suggerire questa catego- ria di tumore, soprattutto se associata ad impregnazione leptomeningea. La precoce disseminazione leptomeningea, infatti, è una caratteristica di queste neoplasie e richiede il completamento diagnostico con studio del midollo spinale. La diagnosi differenziale comprende, oltre ai PNET come medulloepiteliomi e medulloblastomi, gli ependimomi anaplastici e, meno frequenti, astrocitomi, oligodendro-
gliomi, ependimomi, teratomi e tumori mesenchimali. La prognosi è infausta con decorso della malattia molto aggressivo, con una media di sopravvivenza di circa 6 mesi - 1 anno dopo l’intervento chirurgico
Ophthalmoplegic migraine: From questions to answers
No full textINTRODUCTION:
The International Classification of Headache Disorders classifies ophthalmoplegic migraine (OM) under "cranial neuralgias and central causes of facial pain." OM is diagnosed when all the following criteria are satisfied: A. At least two attacks fulfilling criterion B. B. Migraine-like headache accompanied or followed within four days of its onset by paresis of one or more of the III, IV and/or VI cranial nerves. C. Parasellar orbital fissure and posterior fossa lesions ruled out by appropriate investigations. In children the syndrome is rare and magnetic resonance (MR) shows strongly enhancing thickened nerve at the root entry zone (REZ).
METHOD:
The authors review the literature focusing on pathogenesis theories.
RESULTS:
The authors suggest that ischemic reversible breakdown of the blood-nerve barrier is the most probable cause of OM and to include MR findings in the hallmarks of the disease.
CONCLUSION:
OM is the same disease in adulthood and childhood, even if in adults the MR imaging findings are negative. In the authors' opinion, OM should be classified as migraine
[Benign epilepsy in childhood with rolandic and/or mid-temporal paroxysmal EEG discharges: study of the intercritical and critical activity during sleep]
No full text
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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