1,721,294 research outputs found
Characterization of hypersecreting or non-hypersecreting adrenal adenomas: comparison between iodine-131 nor-cholesterol scintigraphy and magnetic resonance imaging.
No full textThe aim of this study was to compare the results of nor-cholesterol scintigraphy and those of magnetic resonance imaging (MRI) in characterizing adrenal adenomas and differentiating between hypersecreting and non-hypersecreting lesions. We studied 41 patients (18 M and 23 F, mean age 47±15 years) with hypersecreting (n=19) or non-hypersecreting (n=22) unilateral adrenal tumors; all patients underwent iodine-131 nor-cholesterol adrenal scintigraphy and MRI studies. Pathology examinations (n=26) or follow-up data (n=15) were obtained showing 34 adenomas, 2 cysts, 1 myelolipoma, 1 pheochromocytoma, 1 carcinoma and 2 metastases. Imaging studies were qualitatively evaluated and the corresponding results were classified as true-positive, true-negative, false-positive and false-negative calculating diagnostic accuracy of each test. Imaging studies were also quantitatively assessed comparing nor-cholesterol uptake and MRI signal intensity ratios (SIRs) in hypersecreting and non-hypersecreting adenomas. The diagnostic accuracies of nor-cholesterol scintigraphy (95%) and MRI (93%) to identify adrenal adenomas were comparable; however, while a significantly (p=0.01) higher nor-cholesterol uptake was observed in hypersecreting (n=19) adenomas compared to non-hypersecreting (n=15) lesions, no significant differences in MRI SIRs were found in this comparative analysis; furthermore, no significant difference in tumor size occurred between hypersecreting and non-hypersecreting adenomas. In conclusion, adrenal scintigraphy using nor-cholesterol and MRI are both able to accurately identify cortical adenomas; in particular, while quantitative analysis of nor-cholesterol uptake is effective to differentiate between hypersecreting and non-hypersecreting adenomas, MRI SIRs evaluation is not useful for this purpose. These findings have relevant clinical implications particularly in patients with non-hypersecreting adenomas; in such patients, laboratory data are not helpful for lesion diagnosis, while imaging findings allow tumor characterization; in particular, the lower nor-cholesterol uptake observed in non-hypersecreting adenomas might reflect the normal hormone synthesis status of these lesions and, thus, regular secretion
Increasing evidence of pathogenic role of the Mediator (MED) complex in the development of cardiovascular diseases
No full textCardiovascular diseases (CVDs) are the first cause of death in the World. Mediator (MED) is an evolutionarily conserved protein complex, which mediates distinct protein-protein interactions. Pathogenic events in MED subunit have been associated with human diseases. Novel increasing evidence showed that missense mutations in MED13L gene are associated with transposition of great arteries while MED12, MED13, MED15, and MED30, have been correlated with heart development. Moreover, MED23 and MED25 have been associated with heart malformations in humans. Relevantly, MED1, MED13, MED14, MED15, MED23, MED25, and CDK8, were found modify glucose and/or lipid metabolism. Indeed, MED1, MED15, MED25, and CDK8 interact in the PPAR-and SREBP-mediated signaling pathways. MED1, MED14 and MED23 are involved in adipocyte differentiation, whereas MED23 mediates smooth muscle cell differentiation. MED12, MED19, MED23, and MED30 regulate endothelial differentiation by alternative splicing mechanism. Thus, MEDs have a central role in early pathogenic events involved in CVDs representing novel targets for clinical prevention and therapeutic approaches. (C) 2019 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved
Imaging integrato delle lesioni espansive delle ghiandole surrenaliche
No full textLa valutazione diagnostica dei pazienti con lesioni espansive delle ghiandole surrenaliche comprende lo studio della funzione e successivamente della struttura anatomica ghiandolare; infatti, l’integrazione delle informazioni riguardo lo stato funzionale e morfologico dei surreni consente di caratterizzare nella maggioranza dei casi la natura delle masse surrenaliche; in particolare, lo studio non invasivo mediante tecniche di diagnostica per immagini di tali pazienti può essere effettuato utilizzando l’ecografia (US), la tomografia computerizzata (TC), la risonanza magnetica (RM) e le metodiche scintigrafiche di medicina nucleare. Nonostante l’US sia un esame poco costoso ed invasivo mostra una minore accuratezza per la valutazione anatomica dei surreni in confronto alla TC ed alla RM. Attualmente, l’imaging integrato ottenuto dai risultati delle immagini della TC, della RM e degli esami scintigrafici rappresenta l’approccio diagnostico più appropriato nello studio delle affezioni delle ghiandole surrenaliche; a tale scopo la tecnica “ibrida” rappresentata dalla PET/TC combina simultaneamente le informazioni diagnostiche di tipo metabolico-funzionale fornite dalla PET con quelle anatomico-strutturali offerte dalla TC. In particolare, la medicina nucleare, in seguito alla sintesi di radiofarmaci specifici per lo studio delle diverse componenti delle ghiandole surrenaliche ed al perfezionamento delle apparecchiature tomografiche (SPECT, PET, PET/TC), ha assunto un ruolo rilevante nell'iter diagnostico dei pazienti con lesioni espansive a sede surrenalica; la scintigrafia cortico-surrenalica con composti radio-iodati colesterolo-affini consente la valutazione della iperplasia corticale, dell'adenoma e del carcinoma surrenalico; la scintigrafia con metaiodobenzilguanidina (MIBG) radio-iodata consente la caratterizzazione dell’iperplasia della componente midollare, del feocromocitoma e del neuroblastoma; gli analoghi della somatostatina radio-marcati sono stati proposti allo scopo di identificare la presenza dei recettori per la somatostatina a livello di lesioni surrenaliche di origine neuroendocrina o di natura maligna; infine, l'impiego nella PET/TC di un tracciante metabolico come il fluoro-18 (F-18) desossiglucosio (FDG), emettitore di positroni, è stato dimostrato essere utile per differenziare le lesioni surrenaliche maligne da quelle benigne. In conclusione, l’integrazione delle informazioni diagnostiche di tipo anatomico offerte dalla TC e/o RM con quelle di tipo metabolico-funzionali ottenute dagli esami scintigrafici consentono un’accurata caratterizzazione delle formazioni espansive surrenaliche evitando nella maggioranza dei casi l’invasività di un’esame bioptico delle lesioni surrenaliche
Comparison between cortical distribution of I-123 iomazenil and Tc-99m HMPAO in patients with Alzheimer's disease using SPECT.
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Cerebral microstructural abnormalities in impulsivity: a magnetic resonance study
No full textStudies that investigated neurobiological parameters subtended to impulsivity trait found their relationship with structural and functional brain alterations. No studies investigated the white matter microstructural attributes of impulsivity in a large sample of healthy subjects. In the present study 1007 subjects from Human Connectome Project public dataset were divided in two groups, impulsive and not impulsive, basing on Delay Discounting task score. For both groups brain morphometric and microstructural characteristics were investigated. A t-test (correct for multiple comparisons) was performed for each brain parcel and impulsivity measure. Magnetic resonance diffusion images were pre-processed and selected to perform a voxelwise analysis on the fractional anisotropy (FA) maps between impulsive and not impulsive groups. Group analysis showed significant differences in morphometric brain data mainly for temporal and frontal lobes. The impulsive group presented higher FA values in four regions: bilateral medial lemniscus and midbrain reticular formation, right superior longitudinal fasciculus, left forceps major, right corticospinal tract. Not impulsive group showed higher FA values in two significant regions: right and left anterior thalamus radiation. Concluding, macroscopic and microstructural brain alterations were assessed, identifying new neuroanatomical substrates for multidimensional impulsivity construct in a large sample of healthy subjects
Congenital agenesis/aplasia of the internal carotid arteries: MRA and SPECT findings.
No full textSingle photon emission CT (SPECT) and MRI and MR angiography studies were performed in a patient with right internal carotid artery (ICA) agenesis, left ICA aplasia, and multiple associated vascular abnormalities identified with digital subtraction angiography. Magnetic resonance angiography provided an excellent depiction of the extra and intracranial vascular abnormalities. No evidence of brain lesions or perfusion defects was demonstrated with MRI and SPECT, despite the markedly altered vascular anatomy
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
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