1,721,468 research outputs found
PRKACA mutations in adrenal adenomas: Genotype/Phenotype correlations
No full textUntargeted, next generation sequencing approaches have provided deep insights into genetic events that result in unopposed steroidogenesis from the adrenal cortex. In particular, somatic mutations in the gene encoding the catalytic subunit α of protein kinase A (PKA) (PRKACA) were identified independently by several groups as the most frequently altered gene in cortisol-producing adenomas. Detailed functional studies could explore the molecular consequences of these hot-spot mutations and large international cohorts have provided the basis to explore the clinical characteristics associated with this mutation. Thereby, PRKACA mutations are highly specific for cortisol over-secretion, while they are absent or very rare in the context of other adrenal diseases. Patients carrying these somatic mutations are affected by a more severe phenotype and are identified at a younger age. Thus, these genotype/phenotype correlations provide further evidence for the importance of PKA-dependent pathways for adrenal physiology and disease
Camp signaling in cortisol-producing adrenal adenoma
No full textThe cAMP signaling pathway is one of the major players in the regulation of growth and hormonal secretion in adrenocortical cells. Although its role in the pathogenesis of adrenocortical hyperplasia associated with Cushing's syndrome has been clarified, a clear involvement of the cAMP signaling pathway and of one of its major downstream effectors, the protein kinase A (PKA), in sporadic adrenocortical adenomas remained elusive until recently. During the last year, a report by our group and three additional independent groups showed that somatic mutations of PRKACA, the gene coding for the catalytic subunit a of PKA, are a common genetic alteration in patients with Cushing's syndrome due to adrenal adenomas, occurring in 35-65% of the patients. In vitro studies revealed that those mutations are able to disrupt the association between catalytic and regulatory subunits of PKA, leading to a cAMP-independent activity of the enzyme. Despite somatic PRKACA mutations being a common finding in patients with clinically manifest Cushing's syndrome, the pathogenesis of adrenocortical adenomas associated with subclinical hypercortisolism seems to rely on a different molecular background. In this review, the role of cAMP/PKA signaling in the regulation of adrenocortical cell function and its alterations in cortisolproducing adrenocortical adenomas will be summarized, with particular focus on recent developments.</p
Adrenal function after adrenalectomy for subclinical hypercortisolism and Cushing's syndrome: A systematic review of the literature
No full textContext: The postoperative course of patients with subclinical hypercortisolism (SH) is yet to be clarified. The aims are to review the prevalence and predictive factors of postoperative adrenal insufficiency and the time to recover a normal adrenocortical function in patients with SH and Cushing's syndrome (CS). Evidence Acquisition: Using the PubMed database, we conducted a systematic review of the literature, selecting studies published from 1980 to 2013. Evidence Synthesis: Of the 1522 papers screened, 28 were selected (13 retrospective, 14 prospective, and one randomized controlled trial). The prevalence of postoperative adrenal insufficiency was 65.3% in 248 SH subjects and 99.7% in 377 CS patients. Patients with SH were reclassified according to the following diagnostic criteria: subjects defined by pathological dexamethasone test only (DEX), and those defined by the dexamethasone test with one (DEX-1) or two additional criteria (DEX+2);andtheywerecomparedwith CS patients. The prevalence of adrenal insufficiency was 51.4, 60.6, 91.3, and 99.7%, respectively, with no significant difference between the two latter groups. The test with the best compromise between sensitivity (64%) and specificity (81%) in predicting adrenal insufficiency was the midnight serum cortisol. The time to achieve eucortisolism was lower in SH patients than in CS patients (6.5 vs 11.2 mo; P < .001). Conclusions: Adrenal insufficiency occurs in about half of the patients with SH if defined only by the pathological dexamethasone test. However, prevalence of adrenal insufficiency and time to recovery are tightly related to the degree of hypercortisolism and diagnostic criteria to define SH, which might help to better define SH for future studies. Copyright © 2014 by the Endocrine Society
The SPARTACUS Trial: Controversies and Unresolved Issues
Full text linkAdrenal vein sampling (AVS) is considered the gold standard for the differential diagnosis in patients with primary aldosteronism (PA). The distinction between unilateral and bilateral disease dictates the targeted therapeutic approach with surgery for aldosterone producing adenomas and medical therapy for patients with bilateral hyperplasia. Thereby, this diagnostic step is crucial in clinical care. As AVS is an invasive, not well standardized procedure that is restricted to few specialized centers, several attempts have been made to simplify diagnostic algorithms. In this clinical scenario, the recently published SPARTACUS trial aimed at answering the question whether AVS in fact is superior for differential diagnosis in comparison to imaging of the adrenal glands. In this multicenter study, patients were randomized to be treated according to AVS results or based on abdominal imaging only. Clinical outcome in both patient groups after one year was reported as not different. While the study results found broad interest, it also stirred considerable controversies. This review provides an overview on the different views regarding the outline of the SPARTACUS trial and the interpretation of its results
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
Human and Murine Cell Lines for Adrenocortical Carcinoma and Pheochromocytoma
Full text linkAdrenocortical carcinoma (ACC) and pheochromocytoma (PCC) are malignancies originating from distinct layers of the adrenal gland. ACCs arise from the adrenal cortex, are often detected at advanced stages and are associated with poor prognosis. PCCs are mostly benign, arise from the adrenal medulla and have a variable prognosis, with 10% of PCCs resulting in metastasis. Genetic background strongly influences metastasis of PCCs, and no reliable biomarkers that predict metastatic behavior exist to date. Current therapeutic strategies for both ACCs and PCCs are overall limited. Thus, novel preclinical models and drug screening approaches need to be established to aid in the identification of more promising drugs and treatment schemes. In this review, we summarize the currently available human and murine cell lines for both tumor entities
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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