294 resultados para thyroid cyst
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Thyroid hormone receptors (TRs) are ligand-gated transcription factors with critical roles in development and metabolism. Although x-ray structures of TR ligand-binding domains (LBDs) with agonists are available, comparable structures without ligand (apo-TR) or with antagonists are not. It remains important to understand apo-LBD conformation and the way that it rearranges with ligands to develop better TR pharmaceuticals. In this study, we conducted hydrogen/deuterium exchange on TR LBDs with or without agonist (T 3) or antagonist (NH3). Both ligands reduce deuterium incorporation into LBD amide hydrogens, implying tighter overall folding of the domain. As predicted, mass spectroscopic analysis of individual proteolytic peptides after hydrogen/ deuterium exchange reveals that ligand increases the degree of solvent protection of regions close to the buried ligand-binding pocket. However, there is also extensive ligand protection of other regions, including the dimer surface at H10-H11, providing evidence for allosteric communication between the ligand-binding pocket and distant interaction surfaces. Surprisingly, Cterminal activation helix H12, which is known to alter position with ligand, remains relatively protected from solvent in all conditions suggesting that it is packed against the LBD irrespective of the presence or type of ligand. T 3, but not NH3, increases accessibility of the upper part of H3-H5 to solvent, and we propose that TR H12 interacts with this region in apo-TR and that this interaction is blocked by T 3 but not NH3.Wepresent data from site-directed mutagenesis experiments and molecular dynamics simulations that lend support to this structural model of apo-TR and its ligand-dependent conformational changes. (Molecular Endocrinology 25: 15-31, 2011). Copyright © 2011 by The Endocrine Society.
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Biomaterials such as membrane barriers and/or bone grafts are often used to enhance periapical new bone formation. A combination of apical surgery and these biomaterials is one of the latest treatment options for avoiding tooth extraction. In case of periapical lesions, guided tissue regeneration (GTR) is attempted to improve the self-regenerative healing process by excluding undesired proliferation of the gingival connective tissue or migration of the oral epithelial cells into osseous defects. In many cases, GTR is necessary for achieving periodontal tissue healing. This report describes the healing process after surgery in a challenging case with a long-term followup. In this case report, endodontic surgery was followed by retrograde sealing with mineral trioxide aggregate (MTA) in the maxillary right central incisor and left lateral incisor. Apicectomy was performed in the maxillary left central incisor and a 1-mm filling was removed. The bone defect was filled with an anorganic bone graft and covered with a decalcified cortical osseous membrane. No intraoperative or postoperative complications were observed. After 13 years of follow-up, the patient showed no clinical signs or symptoms associated with the lesion and radiographic examination showed progressive resolution of radiolucency. In conclusion, the combination of apical surgery and regenerative techniques can successfully help the treatment of periapical lesions of endodontic origin and is suitable for the management of challenging cases.
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Epidermoid cysts are rare benign tumors that are derived from the development of abnormally situated ectodermal tissue and are often an incidental finding. They are usually diagnosed between 15 and 50 years of age, with both sexes equally affected. In epidermoid cyst management, complete excision is the therapy of choice. The authors reported a case of a 24-year-old man with an epidermoid cyst located on the left side of the face, on the region of mandibular body, which was treated by complete surgical excision. The patient has been followed up for 2 years without signs of recurrence. Copyright © 2013 by Mutaz B. Habal, MD.
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Hydrometra is considered a very important pathological condition, because it represents one of the main causes of temporary infertility in dairy goats. The objective was (i) to evaluate a protocol for the treatment of hydrometra associated (n=2) or not (n=17) with follicular ovarian cyst in 19 dairy goats and (ii) to assess its reproductive efficiency after treatment. For this purpose, 10. mg of dinoprost (PGF) divided in two equal doses were administered to all animals intravulvosubmucosally on Days 0 and 10. In addition, 500. IU hCG were administered on Day 7. Ultrasound exams were performed in all females from Days 0 to 3, 7 and 10 to 13 of treatment, in order to evaluate uterus drainage after each treatment. Goats were monitored for estrus after both treatments and mated after the second dose of PGF. Blood samples were collected from 11 goats to determine plasma progesterone concentrations before, during and after treatment. Of the 19 goats treated, 16 lost weight after the first dose, probably due to uterine discharge. Complete drainage of uterine fluid was observed in 11/19 (57.9%) and 17/19 (89.5%) after the first and second doses, respectively. Afterwards, we diagnosed 2 more goats with follicular cysts, for a total of 21.1% (4/19) of animals exhibiting hydrometra and ovarian cyst concomitantly. In one doe the diagnosis was on Day 2 and in the other on Day 11. All does showed progesterone concentrations superior to 1. ng/mL at Day 0, with an average of 10.6 ± 1.4. ng/mL. Out of the 10 goats mated, only two became pregnant after treatment, corresponding to 10.5% of the total (2/19). Although prostaglandin was effective to drain the uterine fluid and led to the onset of estrus, it did not improve the pregnancy rate. The use of hCG in female goats was not effective in luteinizing the cysts. It can be concluded that hydrometra alone or associated with ovarian follicular cyst may adversely affect goat reproductive performance. © 2012 Elsevier B.V.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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A decreased radioiodine uptake is frequently detected in differentiated thyroid carcinomas (DTC) and is associated with high recurrence rate and reduced survival. We investigated the correlation between NIS mRNA expression levels in the primary tumor and patient outcome using a quantitative real-time RT-PCR method. NIS expression was decreased in 17 DTC (21.04 +/- 39.66 pg Eq) compared to four autoimune thyroid disease (180.51 +/- 92.63 pg Eq) and 14 normal tissues (75.71 +/- 66.98 pg Eq) (p < 0.0001). The 17 thyroid differentiated carcinoma patients were submitted to surgery complemented by radioiodine ablation and had at least 24 months of follow-up, under levothyroxine continued suppressive therapy. According to their outcome, we could characterize a group of papillary carcinoma patients with aggressive carcinomas, whose NIS mRNA levels were markedly lower than a group with non-aggressive carcinomas (0.62 +/- 0.79 versus 54.87 +/- 53.79: p < 0.005). We suggest that the quantification of NIS mRNA relative levels in the primary tumor may predict poor outcome. (C) 2003 Elsevier Ireland Ltd. All rights reserved.
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Thyroid hormones (THs) have long been known to have regulatory roles in the differentiation and maturation of vertebrate embryos, beginning with the knowledge that hormones of maternal origin are essential for human fetal central nervous and respiratory system development. Precise measurements of circulating THs led to insights into their critically important actions throughout vertebrate growth and development, initially with amphibian metamorphosis and including embryogenesis in fishes. Thyroid cues for larval fish differentiation are enhanced by glucocorticoid hormones, which promote deiodinase activity and thereby increase the generation of triiodothyronine (T-3) from the less bioactive thyroxin (T-4). Glucocorticoids also induce the expression of thyroid hormone receptors in some vertebrates. Maternally derived thyroid hormones and cortisol are deposited in fish egg yolk and accelerate larval organ system differentiation until larvae become capable of endogenous endocrine function. Increases in the T-3/T-4 ratio during larval development may reflect the regulatory importance of maternal thyroid hormones. Experimental applications of individual hormones have produced mixed results, but treatments with combinations of thyroid and corticoid hormones consistently promote larval fish development and improve survival rates. The developmental and survival benefits of maternal endocrine provisioning are increased in viviparous fishes, in which maternal/larval chemical contact is prolonged. Treatments with exogenous thyroid and corticoid hormones consistently promote development and reduce mortality rates in larval fishes, with potential hatchery-scale applications in aquaculture.
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The thyroid gland was assessed by ultrasound in healthy euthyroid mixed-breed medium size dogs in different age groups. The objective was to verify ultrasonographic imaging patterns in these groups, as well as to identify possible changes in imaging features resulting from ageing. Thirty dogs - 10 young (<1 year), 10 adult and 10 elderly - without clinical signs or history of thyroid gland disease with complete blood count and thyroid function tests within the reference values were evaluated. Each thyroid lobe was examined by ultrasound for shape, size, echogenicity and echotexture. The analysis of echogenicity and echotexture was made by histogram. Thyroid volume was estimated by the equation for ellipsoid (length x width x height) pi/6. The thyroid volume of the young dogs in this study had a tendency to be higher than in adult dogs (P = 0.068) and older dogs (P = 0.120). The height of the thyroid lobe in the longitudinal plane was significantly higher (P = 0.026) in young dogs compared with the other dogs. The echotexture and echogenicity had no significant differences between groups, but the echogenicity was greater in older dogs. The results point out that ultrasound imaging of the thyroid volume is influenced by age in euthyroid dogs.
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The sonographic evaluation of thyroid glands in veterinary medicine presents challenges due to the complexity of the anatomical region, professional experience and type of ultrasonography equipment. The technique is considered a versatile diagnostic method that is noninvasive and has a low cost indicated in different clinical situations. Thyroid carcinoma is a malignant tumor that is often invasive and frequently metastatic to regional lymph nodes and lungs. The prognostic indicators for survival after surgery include tumor size, histological type, mobility and presence or absence of metastasis. The objective of the present report is to demonstrate the importance of ultrasound as a complementary method in the evaluation of thyroid carcinoma in dogs. At the Dr. Halim Atique Veterinary Hospital, an eight-year-old male Pit Bull was examined due to a history of firm painless swelling, approximately six inches in diameter, in the ventral cervical region, for about two months. The sonogram showed a nodular area, with defined and regular margins, and heterogeneous hypoechoic parenchyma, with areas of cavitation and swelling of the thyroid. Histopathology of the nodule was consistent with carcinoma. After thyreoidectomy and hormone replacemet, the patient is in good clinical condition.
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The nasopalatine duct cyst (NPDC) is considered to be the most common non-odontogenic cyst in oral cavity. These cysts are usually asymptomatic; however they can result in swelling, pain and drainage. The radiological analysis can reveal a round, oval or heart shaped well-demarcated image, which can be confounding with inflammatory lesions. The aim of this paper is report a clinical case of NPDC in a patient of 33 years old, occurring near a periapical inflammatory lesion. During clinical examination, it was not possible to detect swelling of the anterior palate and patient didn´t complain painful symptoms. Surgical treatment, enucleation, was performed under local anesthesia and there was no post operative complications. Histological results showed the presence of a cuboidal and respiratory epithelium associated with vessels, nerves and inflammatory cells. The patient’s 3 years follow-up was uneventful with subsequent bone regeneration and no sign of the lesion recurrence.
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Spermatogonial stem cells (SSCs) either self-renew or differentiate into spermatogonia that further develop into spermatozoa. Self-renewal occurs when residing in a specific micro-environment (niche) while displacement from the niche would tip the signalling balance towards differentiation. Considering the cystic type of spermatogenesis in fish, the SSC candidates are single type A undifferentiated (A(und)) spermatogonia, enveloped by mostly one niche-forming Sertoli cell. When going through a self-renewal cell cycle, the resulting new single type Aund spermatogonium would have to recruit another Sertoli cell to expand the niche space, while a differentiating germ cell cyle would result in a pair of spermatogonia that remain in contact with their cyst-forming Sertoli cells. In zebrafish, thyroid hormone stimulates the proliferation of Sertoli cells and of type Aund spermatogonia, involving Igf3, a new member of the Igf family. In cystic spermatogenesis, type Aund spermatogonia usually do not leave the niche, so that supposedly the signalling in the niche changes when switching from self-renewal to differentiation. and rzAmh inhibited differentiation of type A(und) spermatogonia as well as Fsh-stimulated steroidogenesis. Thus, for Fsh to efficiently stimulate testis functions, Amh bioactivity should be dampened. We also discovered that Fsh increased Sertoli cell Igf3 gene and protein expression; rzIgf3 stimulated spermatogonial proliferation and Fsh-stimulated spermatogenesis was significantly impaired by inhibiting Igf receptor signaling. We propose that in zebrafish, Fsh is the major regulator of testis functions and, supported by other endocrine systems (e.g. thyroid hormone), regulates Leydig cell steroidogenesis as well as Sertoli cell number and growth factor production to promote spermatogenesis.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)