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Vasculogenesi, anomalie di crescita vascolari della placenta e cardiopatie congenite: uno studio sperimentale, multidisciplinare e multicentrico volto ad individuare una correlazione ad oggi non nota
No full textIntroduzione: Le Cardiopatie Congenite (CC), sono le anomalie congenite più frequenti alla nascita, con un'incidenza di 1 su 100 nati vivi. La placenta è l'organo fetale più complesso, in grado di garantire lo sviluppo e la crescita fetale durante la gravidanza. Sebbene lo sviluppo della placenta e del cuore avvenga in parallelo, il rapporto tra questi due organi risulta sconosciuto e trattato solo di recente.
Metodi: Abbiamo condotto uno studio osservazionale retrospettivo, includendo i pazienti nati esclusivamente presso l'ospedale G. Gaslini, tra gennaio 2014 e marzo 2018 con una diagnosi prenatale di CC e un’analisi anatomopatologica della placenta, per un totale di 151 pazienti.
I feti affetti da CC sono stati divisi in 5 categorie, basate sulla fisiologia cardiovascolare, come segue: (1) ventricolo singolo con ostruzione aortica, (2) ventricolo singolo con ostruzione polmonare, (3) due ventricoli emodinamicamente instabili, (4) trasposizione delle grandi arterie, (5) due ventricoli emodinamicamente stabili.
Per ogni paziente, sono stati considerati i seguenti dati: peso placentare assoluto, alterazioni macroscopiche e vascolari del cordone ombelicale, indice di massa corporea materna (BMI), genere, restrizione di crescita intrauterina fetale e neonatale (IUGR), anomalie extracardiache, procedura chirurgica o percutanea nel periodo neonatale.
Per l’analisi statistica è stato utilizzato il test esatto di Fisher, con il quale abbiamo studiato il rapporto di dipendenza fra una specifica variabile e le CC; un p <0,05 è stato ritenuto significativo per la dipendenza.
Risultati: Solo quattro variabili hanno mostrato una significatività scientifica: l'intervento neonatale (p = 0,000008), le anomalie associate extracardiache (p = 0,012), l'edema del cordone ombelicale (p = 0,007) e il genere (p = 0,015).
Nonostante avessimo riscontrato un'alta incidenza di inserimento anomalo del cordone ombelicale nelle placente di neonati cardiopatici, il risultato dell’analisi di Fisher non ha dimostrato alcuna
dipendenza tra i gruppi CC e questa variabile (p = 0,379).
Conclusione: Dallo studio dei nostri risultati, non riteniamo che il peso della placenta possa predire
la diagnosi di CC, come precedentemente riportato in letteratura.
Sulla base della nostra esperienza, non possiamo considerare l'inserimento anormale del cordone
come un fattore ad alto rischio per CC. Pertanto, non riteniamo necessario ampliare la metodica di
screening ecografico mediante l’analisi della modalità di inserimento del cordone.
Contrariamente, la presenza di edema del cordone ombelicale è risultata dipendente dalle CC
quindi, potrebbe essere ritenuto un fattore di rischio per CC. Analogamente, anche il genere è
risultato dipendente dalle CC, con una forte associazione fra il sesso maschile e le CC Mayor.
Per il futuro, riteniamo necessario implementare lo studio con l’inserimento di un gruppo di
controllo e con l’inclusione di altre variabili cliniche e strumentali del feto e della placenta.Introduction: Congenital heart diseases (CHD) are the most frequent congenital anomalies at birth, with an incidence of 1 in 100 live births. The placenta is the most complex fetal organ, responsible of fetal development and growth during pregnancy. Although the development of the placenta and heart occurs in parallel, the relationship between these two organs is unknown and only recently elucidated.
Methods: We conducted a retrospective observational study, including patients born exclusively at the G. Gaslini hospital, between January 2014 and March 2018 with a prenatal diagnosis of CHD and an anatomopathological analysis of the placenta, for a total of 151 patients.
Fetuses with CHD Mayor were divided into 5 categories, based on cardiovascular physiology, as follows: (1) single ventricle with aortic obstruction, (2) single ventricle with pulmonary obstruction, (3) two hemodynamically unstable ventricles, (4) transposition of the great arteries, (5) two hemodynamically stable ventricles.
For each patient, the following data were considered: absolute placental weight, macroscopic and vascular alterations of the umbilical cord, maternal body mass index (BMI), gender, fetal and neonatal intrauterine growth restriction (IUGR), extracardiac anomalies, surgical procedure or percutaneous in the neonatal period.
For statistical analysis, the Fisher test was used, with which we studied the dependency ratio between a specific variable and the CHD; a p <0.05 was considered significant.
Results: Only four variables showed scientific significance: neonatal surgery (p = 0.000008), associated extracardiac anomalies (p = 0.012), umbilical cord edema (p = 0.007) and gender (p = 0.015).
Although we had found a high incidence of abnormal insertion of the umbilical cord in the placentas of heart disease infants, the result of Fisher's analysis showed no dependence between the CHD groups and this variable (p = 0.379).
Conclusion: From the analysis of our results, we do not believe that the weight of the placenta can predict the diagnosis of CHD, as previously reported in the literature.
Based on our experience, we cannot consider abnormal cord insertion as a high risk factor for CHD. Therefore, we do not consider it necessary to expand the ultrasound screening method by analyzing the cord insertion method.
Conversely, the presence of edema of the umbilical cord was found to be CHD dependent therefore, it could be considered a risk factor for CHD. Similarly, gender was also dependent on CHD, with a strong association between the male sex and CHD Mayor.
For the future, we believe it is necessary to implement the study with the inclusion of a control group and with the inclusion of other clinical and instrumental variables of the fetus and placenta
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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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