939 resultados para thyroid gland


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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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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Even though the presence of the female prostate has been reported in many species, including humans, bats and several rodents, it has many anatomical and histological variations. There is still plentiful discussion on the biological function of this organ. Many authors state that paraurethral ducts and glands are functional and homologous to the male prostate. The use of experimental models and a better knowledge of the female prostate gland in other species, can be useful to veterinary medicine as well as human medicine. Therefore the aim of this study is to check for the presence of this gland in female dogs of various breeds and age. For that purpose 25 urethras, from the bladder to the vulva, were collected, fixed in 10% neutral buffered formalin, routinely processed and sectioned into 4 slides of 4 µm, each with 40 µm gap between each set of 4 slides, using an automatic microtome and stained with Hematoxylin and Eosine (HE). The HE sections were evaluated for the presence of prostatic gland in the sample. Unstained tissue sections cut from paraffin blocks were marked with a polyclonal anti-PSA primary antibody. The prevalence of the gland was 32% (8/25). The structure of the paraurethral PSA-positive gland was acinar, organized in buds, with secretory epithelium varying from cubic to columnar; eccentric nuclei, with lose chromatin and a layer of basal cells, very similar to the male prostate were observed. In view of these characteristics, for the first time in the literature, was demonstrate that those glands. may be considered as female prostate in dogs, as they are in other vertebrates

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Richards' gland is known for the majority of Epiponini wasps, and despite few experimental evidences, the taxonomic distribution in swarm-founder species and the function of this gland remain rather unclear. This work presents a morphological description of Richards' gland in Protonectarina sylveirae. The gland is formed by a cluster of class 3 cells underneath the anterior margin of the fifth metasomal sternite, and a reservoir formed by the intersegmental membrane between the fourth and fifth metasomal sternites where the secretion can be stored. The secretory cells contain a branched end apparatus that carries the secretory products towards the duct cell. Externally, the cuticle of the sternite, where the duct cells penetrate, is characterized by modifications as scales with very numerous pores. The presence of Richards' gland according to the model proposed by Samacá et al. 2013 in Protonectarina corroborates the single origin of this gland in Epiponini. The occurrence of a Golgi apparatus and smooth endoplasmic reticulum suggests pheromone production.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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In order to evaluate some factors likely to be involved in the maternal and fetal growth impairment due to alimentary protein deficiency, the circulating levels of triiodothyronine (T 3) and thyroxine (T 4) were studied in 4 young (45-day-old) female rat groups: control and malnourished, both nonpregnant and pregnant; similarly schedules groups were studied using adult (100-day-old) rats. Circulating levels of T 4 were higher in nonpregnant, malnourished young rats in their corresponding controls. T 3 levels were higher in young malnourished animals and lower in adult malnourished animals, nonpregnant or pregnant, as compared to controls. Pups from young malnourished mothers showed significantly lower birth weights than those from controls. The present results suggest that there are age differences in thyroid function, as affected by protein-calorie malnutrition in pregnant and non-pregnant rats. On the other hand, the circulating thyroid hormone levels were not importantly affected by the mother dietary protein restriction under our experimental conditions.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Objectives. To compare the frequency of another primary malignancy in patients with differentiated thyroid carcinoma (DTC) who received radioiodine therapy or not ((131)I). Material and Methods. 168 cases of DTC patients were retrospectively evaluated as to the frequency of another neoplasia by comparing patients with and without it, taking into account clinical, laboratory, and therapeutic parameters. Results. Another primary malignancy occurred in 8.9% of patients. Of these, 53.3% showed the malignancy before (131)I and 46.7% after it. By comparing both groups, the age at the moment of diagnosis of another neoplasia was 46.1 ± 20.2 years for the group before (131)I therapy and of 69.4 ± 11.4 years for the group after it (P = 0.02). Of the 148 patients treated with (131)I, 4.7% developed another malignancy. The latter were older (61 ± 17 years) than those who did not show another cancer type (44.1 ± 14.2 years) (P < 0.05). Conclusion. The frequency of another neoplasia found after (131)I was similar to that found before (131)I.

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We investigated thyroid hormone levels in menopausal BrC patients and verified the action of triiodothyronine on genes regulated by estrogen and by triiodothyronine itself in BrC tissues. We selected 15 postmenopausal BrC patients and a control group of 18 postmenopausal women without BrC. We measured serum TPO-AB, TSH, FT4, and estradiol, before and after surgery, and used immunohistochemistry to examine estrogen and progesterone receptors. BrC primary tissue cultures received the following treatments: ethanol, triiodothyronine, triiodothyronine plus 4-hydroxytamoxifen, 4-hydroxytamoxifen, estrogen, or estrogen plus 4-hydroxytamoxifen. Genes regulated by estrogen (TGFA, TGFB1, and PGR) and by triiodothyronine (TNFRSF9, BMP-6, and THRA) in vitro were evaluated. TSH levels in BrC patients did not differ from those of the control group (1.34 ± 0.60 versus 2.41 ± 1.10  μ U/mL), but FT4 levels of BrC patients were statistically higher than controls (1.78 ± 0.20 versus 0.95 ± 0.16 ng/dL). TGFA was upregulated and downregulated after estrogen and triiodothyronine treatment, respectively. Triiodothyronine increased PGR expression; however 4-hydroxytamoxifen did not block triiodothyronine action on PGR expression. 4-Hydroxytamoxifen, alone or associated with triiodothyronine, modulated gene expression of TNFRSF9, BMP-6, and THRA, similar to triiodothyronine treatment. Thus, our work highlights the importance of thyroid hormone status evaluation and its ability to interfere with estrogen target gene expression in BrC samples in menopausal women.

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A case of primary squamous-cell carcinoma (SCC) of the thyroid which had been initially diagnosed as an anaplastic carcinoma (ATC) is described: female, 73 years old, with a fast-growing cervical nodule on the left side and hoarseness for 3 months. Ultrasonography showed a 4.5 cm solid nodule. FNA was compatible with poorly differentiated carcinoma with immunoreactivity for AE1/AE3, EMA. Thyroidectomy was performed. Histopathological examination showed a nonencapsulated tumor. Immunohistochemistry disclosed positivity for AE1/AE3, p53,p63, and Ki67. The diagnosis was ATC. A second opinion reported tumor consisting of squamous cells, with intense inflammatory infiltrate both in tumor and in the adjacent thyroid, with final diagnosis of SCC, associated with Hashimoto thyroiditis. No other primary focus of SCC was found. Patient has shown a 48-month survival period. Clinically, primary SCCs of the thyroid and ATCs are similar. The distinction is often difficult particularly when based on the cytological analysis of FNA material.

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The thyroid hormones (THs), triiodothyronine (T3) and thyroxine (T4), are essential for survival; they are involved in the processes of development, growth, and metabolism. In addition to hyperthyroidism or hypothyroidism, THs are involved in other diseases. The role of THs in the development and differentiation of mammary epithelium is well established; however, their specific role in the pathogenesis of breast cancer (BC) is controversial. Steroid hormones affect many human cancers and the abnormal responsiveness of the mammary epithelial cells to estradiol (E2) in particular is known to be an important cause for the development and progression of BC. The proliferative effect of T3 has been demonstrated in various types of cancer. In BC cell lines, T3 may foster the conditions for tumor proliferation and increase the effect of cell proliferation by E2; thus, T3 may play a role in the development and progression of BC. Studies show that T3 has effects similar to E2 in BC cell lines. Despite controversy regarding the relationship between thyroid disturbances and the incidence of BC, studies show that thyroid status may influence the development of tumor, proliferation and metastasis.

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Bisphenol A (BPA) is one hormonally active chemical with potential deleterious effects on reproductive organs, including breast and prostate. In contrast, genistein (GEN) is the major phytoestrogen of soy that presents potential protective effects against hormone-dependent cancers, including that of the prostate. Thus, pregnant Sprague-Dawley rats were treated with BPA at 25 or 250 μg/kg/day by gavage from gestational day (GD) 10-21 with or without dietary GEN at 250 mg/kg/chow (∼5.5 mg/kg/day). Then, male offspring from different litters were euthanized on post-natal day (PND) 21 and 180. At PND21, BPA 25 exposure induced early prostatic changes while dietary GEN attenuated some deleterious actions this xenoestrogen on epithelial cell proliferation levels, androgen receptor expression and prostatic architecture in male offspring. At PND180, a significant increase in incidence of prostatic multifocal inflammation/reactive hyperplasia and atypical hyperplasia were observed in male offspring from dams that received BPA 25. On the other hand, maternal GEN feeding attenuated some the adverse effects of BPA 25 on prostate disease at late-in-life. This way, the present findings point to preventive action of dietary GEN on deleterious effects of gestational BPA exposure in both early and late prostate development in offspring F1.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)