1,721,007 research outputs found
The Clinical Significance of Subclinical Thyroid Dysfunction.
Full text linkSubclinical thyroid disease (SCTD) is defined as serum free T(4) and free T(3) levels within their respective reference ranges in the presence of abnormal serum TSH levels. SCTD is being diagnosed more frequently in clinical practice in young and middle-aged people as well as in the elderly. However, the clinical significance of subclinical thyroid dysfunction is much debated. Subclinical hyper- and hypothyroidism can have repercussions on the cardiovascular system and bone, as well as on other organs and systems. However, the treatment and management of SCTD and population screening are controversial despite the potential risk of progression to overt disease, and there is no consensus on the thyroid hormone and thyrotropin cutoff values at which treatment should be contemplated. Opinions differ regarding tissue effects, symptoms, signs, and cardiovascular risk. Here, we critically review the data on the prevalence and progression of SCTD, its tissue effects, and its prognostic implications. We also examine the mechanisms underlying tissue alterations in SCTD and the effects of replacement therapy on progression and tissue parameters. Lastly, we address the issue of the need to treat slight thyroid hormone deficiency or excess in relation to the patient's ag
Benefits of thyrotropin suppression versus the risks of adverse effects
No full textA risk-stratified approach to predict the rate of recurrence and death from thyroid cancer was based on the recently revised American Thyroid Association guidelines. A stratified approach to predict the risk from the adverse effects of L-T4 was devised, taking into account the age of the patient, as well as the presence of preexisting cardiovascular and skeletal risk factors that might predispose to the development of long-term adverse cardiovascular or skeletal outcomes, particularly increased heart rate and left ventricular mass, atrial fibrillation, and osteoporosis. Nine potential patient categories can be defined, with differing TSH targets for both initial and long-term L-T4 therapy
Subclinical Hypothyroidism
Full text linkIMPORTANCE Subclinical hypothyroidism, defined as an elevated serum thyrotropin (often
referred to as thyroid-stimulating hormone, or TSH) level with normal levels of free thyroxine
(FT4) affects up to 10% of the adult population.
OBSERVATIONS Subclinical hypothyroidism is most often caused by autoimmune (Hashimoto)
thyroiditis.However, serum thyrotropin levels rise as people without thyroid disease age; serum
thyrotropin concentrations may surpass the upper limit of the traditional reference range of 4 to
5mU/L among elderly patients. This phenomenon has likely led to an overestimation of the true
prevalence of subclinical hypothyroidism in persons older than 70 years. In patients who have
circulating thyroid peroxidase antibodies, there is a greater risk of progression from subclinical to
overt hypothyroidism. Subclinical hypothyroidism may be associated with an increased risk of
heart failure, coronary artery disease events, and mortality from coronary heart disease. In
addition, middle-aged patients with subclinical hypothyroidism may have cognitive impairment,
nonspecific symptoms such as fatigue, and altered mood. In the absence of large randomized
trials showing benefit from levothyroxine therapy, the rationale for treatment is based on the
potential for decreasing the risk of adverse cardiovascular events and the possibility of
preventing progression to overt hypothyroidism.However, levothyroxine therapymay be
associated with iatrogenic thyrotoxicosis, especially in elderly patients, and there is no evidence
that it is beneficial in persons aged 65 years or older.
CONCLUSIONS AND RELEVANCE Subclinical hypothyroidism iscommonand most individuals can
be observed without treatment. Treatment might be indicated for patients with subclinical
hypothyroidism and serum thyrotropin levels of 10mU/L or higher or for young and middle-aged
individuals with subclinical hypothyroidism and symptoms consistent with mild hypothyroidis
Low and intermediate Risk Differentiated Thyroid Cancer and Radioiodine Remnant Ablation: A systematic review of the literature
No full textBackground: Radioiodine remnant ablation (RRA) has traditionally been one of the cornerstones of differentiated thyroid cancer (DTC) treatment. The decision to use RRA in low (LR) and intermediate risk (IR) patients is controversial. The aim of this review is to examine the evidence of RRA benefit in the staging, follow up, and recurrence prevention in LR and IR DTC patients. Methods: From a PubMed research we selected original papers (OP) using the following inclusion criteria: a) DTC; b) LR and IR patients; C) non-RRA treated patients or RRA vs non-RRA treated groups; d) reporting of the outcome of cancer recurrence; e) published since 2008. Results: Neck ultrasonography is superior to WBS for disease detection in the neck. A rising or declining serum thyroglobulin (Tg) over time provide an excellent positive or negative predictive value, respectively, even in non-RRA treated patients. No OP demonstrating RRA benefit on recurrence in LR patients was found; two OP found no evidence of benefit. We found 11 OP that observed some benefit in reducing recurrence rates with RRA in IR patients, and 13 OP that failed to show benefit from RRA in this group. Conclusions: Neck ultrasonography and serum Tg measurement are equivalent or superior in detecting and localizing residual disease compared to RxWBS. There is no evidence of RRA benefit in recurrence prevention for LR patients. There are conflicting data on IR patients, and only a few studies with homogenous and properly stratified populations. A careful evaluation of tumor pathologic features and patient characteristics and preferences should guide RRA decision making
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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