Alviclér Magalhães

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Cytological analysis of thyroid nodules detected using ultrasound-guided fine-needle aspiration technique is an efficient method for the diagnosis of well-differenciated tumors such as papillary thyroid carcinoma. However, for between 10 to 30% of all the nodules, the cytological analysis based on fine-needle aspiration biopsies leads to an "indeterminated"(More)
BACKGROUND Proton magnetic resonance spectroscopy of operative specimens has been reported to successfully differentiate normal tissue from malignant thyroid tissue. We used a new high-resolution magnetic resonance spectroscopy technique for the differentiation of benign and malignant thyroid neoplasms. METHODS Histological specimens from 72 patients(More)
Fractionation of the crude methanol extract of the ascidian Cystodytes dellechiajei collected in Brazil yielded two novel alkaloids, sebastianine A (1) and sebastianine B (2). The structures of both 1 and 2 were established by analysis of spectroscopic data, indicating an unprecedented ring system for both compounds, comprising a pyridoacridine system fused(More)
OBJECTIVE To measure infants' breast milk intake and infant growth when their mothers initiated either combined oral contraceptive (COC), levonorgestrel-releasing intrauterine system, or etonogestrel-releasing implant, or copper intrauterine device (IUD) as a reference group. DESIGN Prospective trial. SETTING University-based hospital. PATIENT(S) On(More)
Herein, we report the synthesis and mass spectrometry studies of several N-alkylbenzenesulfonamides structurally related to sulfanilic acid. The compounds were synthesized using a modified Schotten–Baumann reaction coupled with Meisenheimer arylation. Sequential mass spectrometry by negative mode electrospray ionization (ESI(−)-MS/MS) showed the formation(More)
We have studied the molecular dynamics of one of the major macromolecules in articular cartilage, chondroitin sulfate. Applying (13)C high-resolution magic-angle spinning NMR techniques, the NMR signals of all rigid macromolecules in cartilage can be suppressed, allowing the exclusive detection of the highly mobile chondroitin sulfate. The technique is also(More)
Arenosclerins A (2), B (3), and C (4), as well as haliclonacyclamine E (1), are new tetracyclic alkylpiperidine alkaloids isolated from a new species of marine sponge belonging to the order Haplosclerida, Arenosclera brasiliensis, a species endemic to the southeastern Brazilian coast. The alkaloids were isolated as their hydrochloride salts and identified(More)
Two new bromotyrosine-derived alkaloids, caissarine A (1) and caissarine B (2), along with three known biogenetically related alkaloids, aeroplysinin-1, fistularin-3, and the artifact of isolation 2-(3,5-dibromo-4-dimethoxy-1-hydroxy-2,5-cyclohexadien-1-yl)ethanamide, have been isolated from Aplysina caissara, an endemic species of marine sponge from the(More)
Melanoma is a type of cancer that reaches more people in the world, characterized by genetic mutations that trigger the growth of disorganized cells. The diagnosis of skin tumors by invasive techniques has become a risk to the patients, so the search for new non-invasive techniques has been the subject of research in recent years. The objective of this work(More)
Guanylate cyclase-activating protein-2 (GCAP-2) is a retinal Ca(2+) sensor protein. It plays a central role in shaping the photoreceptor light response and in light adaptation through the Ca(2+)-dependent regulation of the transmembrane retinal guanylate cyclase (GC). GCAP-2 is N-terminally myristoylated and the full activation of the GC requires this lipid(More)