Hipotireoidismo em cães: aspectos gerais

Hypothyroidism is a common endocrine disorder in dogs caused by insufficient production and secretion of thyroid hormones. Most affected dogs have primary hypothyroidism that results from lymphocytic thyroiditis, idiopathic thyroid atrophy, or more rarely, neoplastic destruction. Secondary hypothyroidism resulting from inadequate secretion of thyrotropin (thyroid-stimulating hormone –TSH) from the pituitary gland is less commonly recognized. Tertiary hypothyroidism resulting from a deficiency of hypothalamic thyrotropin-releasing hormone (TRH) has not been documented in dogs. The diagnosis of hypothyroidism in dogs is made on the basis of clinical findings, results of routine laboratory and thyroid gland function tests and response to thyroid hormone replacement. Unfortunately, these tests have high sensitivity, but low specificity, for use in the diagnosis of hypothyroidism. Thyroid hormone supplementation is indicated for the treatment of confirmed hypothyroidism and for the diagnoses of the disease through clinical response to trial therapy

Efeito protetor da coenzima Q10 sobre os danos oxidativos da L-Tiroxina no músculo sóleo de ratos: Fabiana Barreiro de Freitas Silva. -

Pós-graduação em Ciência Animal - FMVA

Efeito da coenzima Q10 nos danos oxidativos induzidos pela L-tiroxina no músculo sóleo de ratos

Introduction: skeletal muscles are dynamic tissue that can change their phenotypic characteristics providing a better functional adaptation to different stimuli. L-thyroxine is a hormone produced by the thyroid gland and has been used as an experimental model for stimulation of oxidative stress in skeletal muscle. Coenzyme Q10 (CoQ10) is a fat-soluble provitamin endogenously synthesized and found naturally in foods such red meat, fish, cereals, broccoli and spinach. It has antioxidant properties and potential in the treatment of degenerative and neuromuscular diseases. Objective: to evaluate the protective effect of CoQ10 in the soleus muscle of rats against the oxidative damage caused by L-thyroxine. Methods: the rats were divided in four groups of six animals each: Group 1 (control); Group 2 (coenzyme Q10); Group 3 (L-thyroxine), and Group 4 coenzyme Q10 and L-thyroxine). After euthanasia, blood was collected and serum activity of the enzymes creatine kinase (CK) and aspartate aminotransferase (AST) was analyzed. In the soleus muscle homogenates the factors related to oxidative stress were assessed. Results: CoQ10 protected the soleus muscle against the damage caused by L-thyroxine and favored the maintenance of the antioxidant enzymes glutathione reductase and glutathione peroxidase, the concentration of decreased and oxidized glutathione, and prevented lipid peroxidation. Conclusion: the results indicate that CoQ10 protects rat soleus muscle from oxidative damage caused by L-thyroxine.

Avaliação ultrassonográfica de crianças com hipotireoidismo congênito

To establish benchmarks and study some sonographic characteristics of the thyroid gland in a group of euthyroid children aged up to 5 years as compared with age-matched children with congenital hypothyroidism. Thirty-six children (17 female and 19 male) aged between 2 months and 5 years were divided into two groups - 23 euthyroid children and 13 children with congenital hypothyroidism - and were called to undergo ultrasonography. In the group of euthyroid children (n = 23), mean total volume of the thyroid gland was 1.12 mL (minimum, 0.39 mL; maximum, 2.72 mL); a homogeneous gland was found in 17 children (73.91%) and 6 children (26.08%) had a heterogeneous gland. In the group of children with congenital hypothyroidism (n = 13), mean total volume of the thyroid gland was 2.73 mL (minimum, 0.20 mL; maximum, 11.00 mL). As regards thyroid location, 3 patients (23.07%) had ectopic thyroid, and 10 (69.23%) had topic thyroid, and out of the latter, 5 had a homogeneous gland (50%) and 5, a heterogeneous gland (50%). In the group with congenital hypothyroidism, 6 (46.15%) children had etiological diagnosis of dyshormoniogenesis, 3 (23.07%), of ectopic thyroid, and 4 (30.76%), of thyroid hypoplasia. Thyroid ultrasonography is a noninvasive imaging method, widely available, easy to perform and for these reasons could, and should, be performed at any time, including at birth, with no preparation or treatment discontinuation, to aid in the early etiological definition of congenital hypothyroidism.

Aspectos ultrassonográficos da glândula tireoide hígida em equinos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tiouréia no desenvolvimento de girinos de rã-touro e no desempenho de animais pós-metamórficos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diagnóstico por imagem nas enfermidades tireoidianas em cães: revisão

The diagnosis of various diseases has become more accessible and accurate with the rapid development of imaging modalities aiming to assist in medical diagnosis, and thereby in veterinary medicine. Different diagnostic imaging modalities such as ultrasonography, computed tomography, magnetic resonance imaging and scintigraphy can be performed to obtain information about thyroid diseases, each one with advantages and disadvantages, depending on the thyroid disease in question. Diagnostic imaging is a tool that not only assists in the diagnosis, but also helps treatment and assessment of prognosis of thyroid diseases. The aim of this article is to discuss the limitations and benefits of each diagnostic imaging modality available in the veterinary medical field, and also to present the newest diagnostic imaging modalities in order to maximize and make more accurate diagnosis of thyroid diseases.

Thyroid cell proliferation in Graves' disease - Use of MIB-1 monoclonal antibody

OBJECTIVE: To measure thyroid cell proliferation in patients with Graves' disease (GD) before and during treatment with antithyroid drugs.STUDY DESIGN: Patients were assessed by fine needle aspiration biopsy before (n=20) and after 4 (n=19) and 12 months of treatment (n=15) with propylthiouracil or methimazole. Cell proliferation index (CPI) was estimated by immunocytochemistry using MIB-1. CPI was studied in relation to the cytologic parameters of the smears; clinical parameters, such as Wayne's Clinical Index (WCI) and time without treatment; laboratory parameters, such as (131)Iuptake and dosage of serum free thyroxin and thyroid-stimulating hormone; and thyroid ultrasound.RESULTS: CPI varied from 0.00% to 25.00% before treatment, 0.00% to 23.00% at 4 months and 0.00% to 14.84% at 12 months. CPI median values were 6.50%, 4.30% and 3.30%, respectively (before and after 4 months and 12 months of treatment). CPI had a positive correlation with WCI and FT4 at 12 months of treatment.CONCLUSION: Thyroid CPI in GD varies from case to case. However, due to its decreasing pattern during follow-up and its positive correlation with thyrotoxicosis severity, CPI may indicate the functional status of the gland and contribute to a better understanding of GD.

Evaluation of quality of life related to i-131 therapy in patients with well-differentiated thyroid cancer and emphasis in salivary morbidity: a follow up study after treatment

To evaluate the impact of iodine-131 therapy received during childhood and adolescence and correlate it with the quality of life in these patients. Methods: We studied 19 patients diagnosed with cancer in childhood or adolescence who underwent thyroidectomy and supplemental therapy with I-131. We also recruited a control group of healthy subjects with the same demographic parameters. All patients were subjected to a scintigraphy examination of the salivary glands, and were also asked to complete a questionnaire in order to assess their overall quality of life. In addition, a more specific questionnaire for patients with head and neck cancer was also given to all study participants. Results: The quantitative and qualitative analyses of the salivary glands showed functional deficits with greater involvement of the parotid gland for volume, concentration and excretion. The right submandibular gland showed significant changes for volume in the patient group. The questionnaires made it possible to observe significant differences between the patient and control groups for symptoms such as thick saliva, dry mouth and speech problems. Conclusion: In spite of being very effective and widely used, iodine radionuclide therapy is correlated with a lower quality of life in young people.

Structural and ultrastructural characteristics of interrenal gland and chromaffin cell of matrinxa, Brycon cephalus Gunther 1869 (Teleostei-Characidae)

This work presents the structure and ultrastructure of the interrenal gland and chromaffin cells, as well as the morphology of the head kidney of Brycon cephalus, the head kidney is composed of fused bilateral lobes located anterior to the swim bladder and ventrolateral to the spinal column, the parenchyma revealed lympho-haematopoietic tissue, melano-macrophage centres, interrenal gland and chromaffin cells. The interrenal gland consisted of cords or strands of cells grouped around the posterior cardinal vein and their branches. Chromaffin cells are found in small groups, closely associated with the interrenal gland and/or under the endothelium of the posterior cardinal vein. So far, the ultrastructural analysis has revealed only one interrenal cell type which contained abundant smooth endoplasmic reticulum and numerous mitochondria with tubulo-vesicular cristae, characteristic of steroid-producing cells. Two types of chromaffin cells were observed. The first type was characterized by the presence of vesicles with round, strongly electron-dense granules, which were eccentrically located, Such cells were interpreted as noradrenaline cells, Meanwhile, cells which contained smaller vesicles and electron-lucent granules, with a small halo separating the granule from the vesicular limiting membrane, were identified as adrenaline cells.

Third eyelid gland protrusion in dogs: an experimental model proposal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Somatotrophic and thyroid hormones around the onset of lay in broiler breeders under different conditions

Somatotrophic and thyroid hormones were determined around the onset of reproduction in broiler breeders reared in two different housing systems [dark, close-sided house (CH) and conventional, open-sided house (OH)]. In both groups age-related changes were obvious for thyroxine (T-4), growth hormone (GH) and insulin-like growth factor (IGF-1); levels of T-4 decreased, especially between 24 and 28 weeks in both groups; concomitantly GH sharply increased over the same period. A transient peak in triiodothyronine (T-3) occurred between 25 and 27 weeks. The effect of housing was only present after the onset of lay. Between weeks 27-28 and the end of the period studied, the CH group showed higher levels of GH and T-3 but lower T-4 levels as compared to the OH group. A significant increase in GH after onset of lay, without any significant rise in T-3 or in IGF-I, could point to a relative insensitivity to high plasma GH levels. Changes at GH receptor level, together with an increased pituitary GH secretion and/or decreased GH turnover may be expected. This may indicate that hypothalamo-pituitary changes at the onset of lay not only imply changes of gonadotrophic cell function, but also other hormonal axes. The relatively decrease in T-4 without changes in T-3, may point to a decrease in the activity of the thyrotropic axis.

Large-scale transcriptome analyses reveal new genetic marker candidates of head, neck, and thyroid cancer

A detailed genome mapping analysis of 213,636 expressed sequence tags (EST) derived from nontumor and tumor tissues of the oral cavity, larynx, pharynx, and thyroid was done. Transcripts matching known human genes were identified; potential new splice variants were flagged and subjected to manual curation, pointing to 788 putatively new alternative splicing isoforms, the majority (75%) being insertion events. A subset of 34 new splicing isoforms (5% of 788 events) was selected and 23 (68%) were confirmed by reverse transcription-PCR and DNA sequencing. Putative new genes were revealed, including six transcripts mapped to well-studied chromosomes such as 22, as well as transcripts that mapped to 253 intergenic regions. In addition, 2,251 noncoding intronic RNAs, eventually involved in transcriptional regulation, were found. A set of 250 candidate markers for loss of heterozygosis or gene amplification was selected by identifying transcripts that mapped to genomic regions previously known to be frequently amplified or deleted in head, neck, and thyroid tumors. Three of these markers were evaluated by quantitative reverse transcription-PCR in an independent set of individual samples. Along with detailed clinical data about tumor origin, the information reported here is now publicly available on a dedicated Web site as a resource for further biological investigation. This first in silico reconstruction of the head, neck, and thyroid transcriptomes points to a wealth of new candidate markers that can be used for future studies on the molecular basis of these tumors. Similar analysis is warranted for a number of other tumors for which large EST data sets are available.

TLR4 and CD14 receptors expressed in rat pineal gland trigger NFKB pathway

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

Tireóide ectópica cervical lateral: Relato de caso e revisão da literatura

Tireóide ectópica é qualquer tecido tireoideano localizado fora de sua topografia habitual, podendo apresentar-se na linha mediana do pescoço ou, mais raramente, na região cervical lateral. Algumas teorias tentam explicar a origem do tecido tireoideano ectópico: 1. falha na descida da glândula; 2. seqüestro de nódulos tireoideanos; 3. presença de tecido tireoideano na cápsula de linfonodos cervicais; 4. formação teratomatosa; 5. Secundário a anomalias branquiais. Na abordagem diagnóstica, diversos exames têm sido utilizados, sendo o diagnóstico definitivo algumas vezes fornecido apenas pelo estudo histopatológico. Apesar das controvérsias em relação às abordagens terapêuticas apresentadas na literatura, é necessário um planejamento rigoroso para evitar iatrogenias. Conclui-se que a presença de tecido tireoideano ectópico deve ser lembrada no diagnóstico diferencial de massas cervicais laterais, e sua origem histológica considerada, sendo na maioria das vezes metástase de um carcinoma tireoideano oculto. Os autores relatam um caso de tecido tireoideano ectópico lateral no pescoço, em paciente do sexo feminino com bócio colóide mergulhante. Foram realizadas considerações importantes sobre dismorfogênese tireoideana, métodos diagnósticos e opções de tratamento, com revisão da literatura das últimas cinco décadas.