1,720,974 research outputs found
Influence of iodization programmes on the epidemiology of nodular goitre
Full text linkIodine is essential for the synthesis of thyroid hormones. Iodine deficiency can affect human health in different ways, and is commonly referred to as iodine deficiency disorders (IDD). These range from defective development of the central nervous system during the fetal-neonatal life, to goitre in the adult. Only a few countries were completely iodine sufficient before 1990. Since then, a major effort has been made to introduce salt iodization to ensure sufficient intake of iodine in deficient areas. Iodine prophylaxis has been shown to exert a pivotal role in abating goitre and other iodine-deficiency disorders, and has also been shown to modulate the pattern of thyroid diseases. An increased frequency of thyroid autoimmunity and of hypothyroidism has been observed after introducing iodization programmes. Nevertheless, available evidence clearly confirms that the benefits of correcting iodine deficiency, consisting mainly of reducing nodular goitre and non-autoimmune hyperthyroidism, far outweigh the risks of iodine supplementation
Iodine, thyroid autoimmunity and cancer
Full text linkThis review focuses on two different topics: (a) iodine and autoimmune thyroid disease (AITD) and (b) AITD and papillary thyroid carcinoma (PTC). Iodine intake modifies the expression of thyroid diseases and has been associated with induction of AITD. Thyroglobulin (Tg) is an important target in iodine-induced autoimmune response due to post-translational modifications of iodinated Tg, as suggested in animal models. We have shown that the unmasking of a cryptic epitope on Tg contributes to iodine-induced thyroid autoimmunity in humans. The relationship between AITD and PTC has been suggested in many studies. The presence of two different mechanisms has been hypothesized, one typical of AITD and the other of an immune reaction to PTC. We have shown that in AITD, the pattern of Tg recognition by anti-Tg antibodies (TgAb) is 'restricted' to the immunodominant regions of Tg, while in patients with non-AITD, such as nodular goiter and PTC devoid of thyroid lymphocytic infiltration at histology, TgAb show a less restricted epitopic pattern and bind also to other regions of Tg. Thyroid function may also affect the frequency of PTC, the risk of cancer increasing with serum TSH levels. We have shown that this mechanism, rather than thyroiditis per se, plays a major role in the association of PTC with Hashimoto's thyroiditis, as a consequence of the autoimmune process leading to a progressive increase of serum TSH in these patients
Tiroidite cronica autoimmune
No full textLe malattie autoimmuni della tiroide (Autoimmune Thyroid Diseases, ATD) rappresentano il prototipo delle patologie autoimmuni organo specifiche. Le ATD sono comuni nella popolazione generale (4% in Gran Bretagna) e colpiscono prevalentemente il sesso femminile (1). Si distinguono due forme principali di ATD: il morbo di Basedow e la tiroidite cronica autoimmune (TCA). Queste malattie costituiscono gli estremi di uno spettro di patologie in cui è possibile talvolta osservare l’evoluzione di una forma clinica in un’altra durante il decorso della malattia nello stesso paziente.
La prima descrizione della tiroidite cronica autoimmune risale al 1912 (2), quando Hakaru Hashimoto riportò i casi di 4 donne, tutte di etá superioare ai 40 anni e di cui almeno una clinicamente ipotiroidea, che erano state sottoposte a tiroidectomia per gozzo. All’esame istologico le tiroidi di queste pazienti non presentavano le peculiarità tipiche del gozzo colloide, ma erano caratterizzate dalla presenza di un infiltrato linfocitario diffuso, fibrosi ed atrofia parenchimale. Dopo l’iniziale descrizione di Hashimoto, sono stati riportatati altri casi di questa patologia tiroidea ritenuta inizialmente rara e poi di riscontro sempre più frequente, soprattutto dopo l’introduzione della citologia su agoaspirato. Negli anni 50 è stata dimostrata una patogenesi autoimmunitaria per questa malattia. Nel 1956 Rose and Witebsky (3) dimostrarono che immunizzando conigli con estratti tiroidei si inducevano nelle loro tiroidi alterazioni istologiche simili a quelle osservate nei pazienti descritti da Hashimoto. Successivamente Roitt (4) osservò che incubando il siero di pazienti con tiroidite di Hashimoto con estratti di tiroide umana si formavano precipati, dimostrando la presenza di anticorpi anti tiroide nel siero di questi pazienti.
La tiroidite cronica autoimmune è oramai riconosciuta come il modello delle malattie atuimmuni organo specifiche e può associarsi ad altre patologie autoimmuni organo specifiche (come il morbo di Addison autoimmune, il diabete mellito tipo I, la vitiligine, la gastrite atrofica, l’anemia perniciosa, la miastenia grave) o anche non organo specifiche (come l’artrite reumatoide e il LES).
Le diverse forme di TCA sono indicate nella tabella 1. La tiroidite cronica autoimmune può essere distinta in due forme: la tiroidite di Hashimoto e la variante atrofica. Sul piano clinico la tiroidite di Hashimoto è caratterizzata dalla presenza di un gozzo, di consistenza aumentata alla palpazione, mentre nella variante atrofica la tiroide non è palpabile. La funzione tiroidea può essere conservata (specie nella tiroidite di Hashimoto) o può essere presente ipotiroidismo. La tiroidite focale rappresenta una forma particolare di tiroidite caratterizzata sul piano istologico dalla presenza di infiltrati linfocitari focali, riscontrati spesso in patologie tiroidee non autoimmuni come il gozzo nodulare o il carcinoma tiroideo. La tiroidite post-partum e la tiroidite silente costituiscono due forme transitorie di tiroidite. Si manifestano in soggetti predisposti allo sviluppo di autoimmunità tiroidea ed hanno una durata limitata nel tempo, anche se possono evolvere nella tiroidite cronica autoimmune.
Le diverse possibili manifestazioni cliniche generano spesso confusione nella definizione stessa di tiroidite cronica autoimmune. La presenza di anticorpi anti-tiroide non è sufficiente per la diagnosi di TCA, poiché questi autoanticorpi possono essere presenti in una minoranza di pazienti con malattie tiroidee non autoimmuni e di soggetti normali. In alcuni studi, vengono considerati affetti da TCA solo i pazienti con anticorpi anti tiroide che presentano una disfunzione tiroidea. Tuttavia, anche tale criterio non è completamente corretto, perché vengono esclusi quei pazienti con tiroidite di Hashimoto con una normale funzione tiroidea. Una definizione più corretta di TCA include la presenza di anticorpi anti tiroide associata ad un pattern ecografico ipoecogeno, tipico delle tireopatie autoimmuni, indipendentemente dalla funzione tiroidea. I diversi criteri utilizzati nella definizione di TCA sono responsabili delle differenze epidemiologiche riscontrate in diversi studi e dei risultati discrepanti sul ruolo di fattori genetici ed ambientali nella patogensi di questa malattia
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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