Estudio histomorfométrico de folículos tiroideos humanos con microscopía holográfica digital / Histomorphometric study of human thyroid follicles by digital holographic microscopy

Introducción: La microscopía holográfica digital ha permitido a la microscopía óptica hacer uso de herramientas numéricas y computacionales; y esto, a su vez, ha favorecido múltiples avances en el estudio de las células y los tejidos en diferentes campos de la medicina y otras ciencias afines. Objetivo: Describir las características histológicas y morfométricas de los folículos tiroideos humanos con la microscopía holográfica digital. Métodos: Se realizó, desde el punto de vista histomorfométrico, un estudio descriptivo y transversal de folículos tiroideos humanos utilizando una instalación de microscopía holográfica digital. Se empleó la técnica de inclusión en parafina y tinción de hematoxilina-eosina para el procesamiento de las muestras. Se realizaron de 10 a 12 capturas de hologramas por muestra y el método de doble propagación para la reconstrucción de los hologramas. Se calculó el área, el perímetro, el diámetro mayor y menor de los folículos y cavidades foliculares y se realizaron reconstrucciones de imágenes holográficas en tres dimensiones. Se determinó como medida de tendencia central la media aritmética y como medida de dispersión la desviación típica o estándar. Resultados: Parámetros foliculares: área (5140,31 ± 1126,71 µm2); perímetro (2961,54 ± 71,2 µm); diámetro mayor:(921,17 ± 24,34 µm); diámetro menor: (746,67 ± 18,08 µm); altura del epitelio (7,92 ± 0,96). Cavidades foliculares: área (3686,18 ±1023,52 µm2); diámetro mayor: (698,86 ± 19,55 µm) y diámetro menor: (581,15 ± 13,82 µm). Conclusiones: Existen parámetros foliculares, determinados mediante la microscopía holográfica digital, no reportados por la literatura consultada, que resultan de interés en el estudio histológico de los folículos tiroideos humanos(AU)

Introduction: Digital holographic microscopy has made it possible to incorporate the use of numerical and computer tools into optical microscopy. This in turn has led to great progress in the study of cells and tissues in several fields of medicine and related sciences. Objective: Describe the histological and morphometric characteristics of human thyroid follicles using digital holographic microscopy. Methods: A descriptive cross-sectional histomorphometric study was conducted of human thyroid follicles using a digital holographic microscopy facility. Sample processing was based on inclusion technique by paraffin and hematoxylin-eosin staining. Ten to twelve holographic captures were made per sample, and the double propagation method was used for holographic reconstruction. Estimation was carried out of the area, perimeter, and greatest and smallest diameter of follicles and follicular cavities, and tri-dimensional reconstructions were made of holographic images. Arithmetic mean was determined as the measure of central tendency, and typical or standard deviation as the measure of dispersion. Results: Follicular parameters: area (5 140.31 ± 1 126.71 µm2); perimeter (2 961.54 ± 71.2 µm); greatest diameter (921.17 ± 24.34 µm); smallest diameter (746.67 ± 18.08 µm); epithelial height (7.92 ± 0.96). Follicular cavities: area (3 686.18 ± 1 023.52 µm2); greatest diameter (698.86 ± 19.55 µm); smallest diameter (581.15 ± 13.82 µm). Conclusions: A number of follicular parameters determined by digital holographic microscopy have not been reported by the literature consulted, and they are of interest to the histological study of human thyroid follicles(AU)

Hematology, biochemical profile and thyroid hormones of four species of freshwater stingrays of the genus Potamotrygon / Hematologia, perfil bioquímico e hormônios da tireoide em quatro espécies de arraias de água doce do gênero Potamotrygon

Potamotrygonidae is a family of freshwater stingray endemic in South America. We determined the hematological and serum biochemistry parameters of Potamotrygon motoro and Potamotrygon falkneri from Parana Basin and Potamotrygon orbignyi and Potamotrygon scobina from the Amazon Basin. Blood was collected from 55 specimens of Potamotrygon sp., and these parameters were evaluated: red blood cell count, hematocrit percent, hemoglobin concentration, leucocytes count, trombocytes count, total protein concentration, albumin, uric acid, urea, creatinine, triglycerides, cholesterol, high-density lipoprotein HDL, calcium, phosphorus, calcium/phosphorus relationship, creatine kinase CK, gamma-glutamyl transpeptidase GGT, Aspartate transaminase AST, alanine transaminase ALT, globulin, albumin/globulin relationship, alkaline phosphatase AP, sodium, chloride, potassium, triiodothyronine T3, and thyroxine T4 hormones. The hematological indices were similar for all species, except for levels of heterophils in P. orbignyi and P. scobina that were higher. Calcium, phosphorus, calcium/phosphorus relationship, sodium, potassium, chloride, AST, ALT, GGT, CK, albumin/globulin relationship, uric acid, creatinine, urea, triglycerides, HDL, T3, T4 levels had no significant difference between the species. These results suggest that there is low influence of habitat and feeding habits. AP, total protein, albumin, globulin, glucose, and total cholesterol had significant differences between the studied species. These results support the theory that stingrays migrated from the Atlantic Ocean, adapting to different conditions over time and placed themselves geographically distant from each other.

Potamotrygonidae e um grupo de raias endêmicas da América do Sul distribuídas nas principais bacias hidrográficas brasileiras, mas informações sobre suas variáveis hematológicas e bioquímicas são escassas. Este estudo teve como objetivo determinar estas variáveis em Potamotrygon motoro e P. falkneri na Bacia do Rio Paraná, Estado do Paraná e de P. orbignyi e P. scobina do Rio Piririm, na Bacia Amazônica, Estado do Amapá. Foi capturado um total de 53 espécimes de Potamotrygon spp. para colheita de sangue e avaliações do hemograma e variáveis bioquímicas séricas. Os valores do hemograma foram próximos para as quatro espécies e os resultados com diferenças significativas entre Potamotrygon falkneri, P. motoro, P. orbigni e P. scobina ocorreram quanto ao número de eritrócitos e heterófilos. Apesar da diversidade geográfica os resultados apresentaram pouca interferência dos diferentes habitats nas variáveis avaliadas. Os níveis de proteínas, globulinas, relação albumina:globulina, acido úrico, creatinina, ureia, HDL-C, relação cálcio:fósforo, sódio, cloreto, AST, ALT, creatinoquinase (CK), fosfatase alcalina, hormônios triiodotironina (T3) e tiroxina (T4) não diferiram entre as espécies de Potamotrygon. Porem, os níveis de albumina, glicose, colesterol total, triglicerídeos e gama glutamil transferase (GGT) apresentaram diferenças. Este fato sugere pouca interferência do habitat nas variáveis avaliadas apesar da diversidade geográfica de origem das raias de vida livre.

role of different photoperiods in the activation of the thyroid gland and ovaries of adult and aged rats [Rattus norvegics]

Many animals use the length of the day [photoperiod] to predict and adjust to seasonal changes in the environment through predictive changes in physiology and behaviour. The present work is designed to study the effect of different photoperiod regimes, i.e., short photoperiod 10L:14D, long photoperiod 14L:10D and 12L:12D light-dark cycle [LD] on the structure and hormonal secretion of the thyroid gland and ovaries in adult and aged female rats. The rats were divided into 6 groups, each group contained 6 adults [6 months old] or aged rats [18 months old] and maintained for one month under different photoperiod regimes. Short and long photoperiods increased the activity of the thyroid gland of the adult rats. This gland was full of small follicles lined with simple columnar epithelium. Serum thyroxin levels were extremely higher in long photoperiod group than that observed in 12:12LD and short photoperiod groups. In contrast short photoperiod induced an increase in serum thyroxin level in the aged rats. Short photoperiod and 12:12 LD cycle enhanced gonadal activity of the adult rats. The ovary contained clusters of primordial follicles, different stages of ovarian follicles, and, few numbers of atretic follicles. In the groups of the aged rats all the stages of the ovarian follicles exhibited signs of atresia in such groups. LH, FSH, progesterone and estrogen were increased mainly in the control group in adult and aged rats compared to the photoperiod groups. From the present result we could conclude that: 12:12 light dark cycle enhanced the structural and functional activities of ovaries in adult rats, while aging decreased their activities. In contrast, long photoperiod induced thyroid gland activities in adult rats while short photoperiods activated the gland of aged rats

Thyroid function test in pre-term neonates during the first five weeks of life

Congenital hypothyroidism [CHT] is one of the most common congenital endocrinal disorders. The prevalence of CHT is estimated about 1 in 3,000 newborns. The prevalence, etiology and associated disorders of abnormal thyroid screening tests are reported in different ranges. In this study, we assessed the pre-term newborns for CHT and associated factors that influence thyroid function. One hundred newborns with the gestational age fewer than 35 weeks were investigated. Baseline serum thyroid stimulating hormone [TSH] and free thyroxin [FT4] levels were measured during the first 5 days of life and were repeated during the first 5 weeks. We analyzed the effects of demographic factors and the presence of respiratory distress syndrome on the alteration of thyroid function tests during the first 5 weeks of life. The mean gestational age [GA] at delivery was 32.35 +/- 1.97 [range 28 to 35] weeks. CHT was observed in 13[13%] preterm infants. GA was the only factor which affect the FT4 changes over the two weeks follow-up [P < 0.001, b: -2.783, Power: 70.2%] although the differences between baseline and follow-up amount of TSH were not significantly influenced by GA [P = 0.062, power: 46%]. However, the adjusted TSH and FT4 serum level changes during follow-up were significantly different between two groups [between CHT and normal, P = 0.006, 0.000, respectively]. It seems that thyroid function tests should be repeated in preterm infants, especially for patients with lower gestational age, to confirm the diagnosis of CHT. Also, CHT should be considered among the newborns that are affected by RDS.

Avaliação do peso corporal em pacientes com doença de Graves durante o tratamento com metimazol / Evaluation of body weight in patients with Graves' disease during the treatment with methimazole

OBJETIVO: Avaliar a alteração de peso durante o tratamento do hipertiroidismo e correlacioná-la com IL-6 e TNF-alfa. SUJEITOS E MÉTODOS: Quarenta e dois pacientes foram incluídos. Peso corporal (PC), índice de massa corpórea (IMC), características clínicas e laboratoriais foram registrados. IL-6 e TNF-alfa foram determinados antes do tratamento com metimazol (MMI) e no estado de eutiroidismo. RESULTADOS: O PC foi de 59,62 ± 11,5 kg no estado de hipertiroidismo e de 69,91 ± 14,4 kg no estado de eutiroidismo (p < 0,001). O IMC aumentou de 23,1 ± 3,8 kg/m² para 27 ± 4,7 kg/m² durante o tratamento (p < 0,0001). Antes da terapia, 66,6% tinham IMC < 25 kg/m² e 33,3%, IMC > 25 kg/m². No estado de eutiroidismo, 38% dos pacientes apresentavam IMC < 25 kg/m² e 62%, IMC > 25 kg/m² (p = 0,01). No estado de eutiroidismo, encontrou-se significativa diminuição nos valores de IL-6 e TNF-alfa, mas nenhuma correlação entre IL-6 e TNF-alfa com PC ou IMC. CONCLUSÃO: Um importante aumento no PC e IMC foi observado durante o tratamento do hipertiroidismo e alterações de IL-6 e TNF-alfa relacionam-se somente com o retorno ao eutiroidismo.

OBJECTIVE: To evaluate weight change during hyperthyroidism treatment, and to correlate it with IL-6 and TNF-alpha concentrations. SUBJECTS AND METHODS: Forty two patients were included. Body weight (BW), body mass index (BMI), clinical and laboratory characteristics were recorded. IL-6 and TNF-alpha were determined before treatment with methimazole (MMI) and in euthyroidism. RESULTS: BW was 59.62 ± 11.5 kg in hyperthyroidism, and 69.91 ± 14.4 kg in euthyroidism (p < 0.001). BMI increased from 23.1 ± 3.8 kg/m² to 27 kg/m² ± 4.7 during treatment (p < 0.0001). Before treatment, 66.6% subjects had BMI < 25 kg/m² and 33.3%, BMI > 25 kg/m². In euthyroidism, 38% of patients had BMI < 25 kg/m² and 62%, BMI > 25 kg/m² (p = 0.01). In euthyroidism, we found a significant reduction in IL-6 and TNF-alpha concentrations, but no correlation between IL-6 and TNF-alpha, and BW or BMI. CONCLUSION: An important increase in BW and BMI was observed during hyperthyroidism treatment, and IL-6 and TNF-alpha alterations were only related with return to euthyroidism.

Hormonal dysfunction in patients with chronic obstructive pulmonary disease

Systemic response to chronic disease in COPD patients might cause hormonal imbalance which in turn affects the severity of the disease. The severity of hypoxia in COPD patients causes alterations in thyroid function tests and IGF-1 levels. This work was carried on 50 COPD patients diagnosed and classified according to GOLD criteria and 20 healthy controlled subjects. All subjected to full clinical history, examination, chest X-ray and spirometry. Levels of TT3, TT4, FT3, FT4, IGF-1 and insulin were measured. TT4, FT3, FT4, TSH, and insulin levels were normal in all COPD. Despite the TT3 hormone level were normal in all stages of COPD, there is reduction in hormone levels in stage III and stage IV than control subjects. There is also reduction in TT3/TT4 ratio in severe COPD and there is correlation between TT3/TT4 ratio and PaO2 in stage III and stage IV but no correlation between TT3/TT4 ratio and PaO2 in stage I and stage II. IGF-1 hormone levels were variable among different stages of COPD. There is was no significant difference between some hormonal levels in COPD and in controls, accordingly hormonal replacement therapy in these patients is doubtful

A study on maturation of thyroid gland in human fetuses

The thyroid gland is the first endocrine gland to appear on the embryonic period. Its organogenesis beginswhen the medium endoderm cells start getting thick, forming a diverticulum, in the primitive pharynx floor.In this report, we describe the histological maturation of thyroid gland in human fetuses, correlating the tissueaspects with pregnancy stage. Twenty human fetuses were used in this study in different developmental stages.The fetuses from 20 to 36 weeks (gestational age) were dissected and the thyroid gland removed. The glandwas then embedded in paraffin, cut in frontal plans portions and stained with Hematoxylin and Eosin (H&E).We observed that the maturation process of the thyroid follicles was directly correlated with the gestationalage, where human fetus with 23 weeks of age did not show any sign of follicles or colloid and the one with35 weeks of age presented follicles with colloid. The conclusion of this study was that maturation process ofthe thyroid follicles tissue is a linear process with the fetal development.

Complicaciones obstétricas y neonatales del hipotiroidismo / Obstetrics and neonatal complications of hypothyroidism

Las patologías tiroideas son frecuentes y afectan alrededor del 10% de la población fértil femenina. El hipotiroidismo y la enfermedad tiroidea autoinmune traen aparejados trastornos de la fertilidad e implantación y desarrollo del embarazo. Durante el embarazo la glándula tiroides es puesta a prueba, poniéndose en marcha distintos mecanismos adaptativos. Se debe resaltar la importancia de un aporte suficiente de yodo antes y durante el embarazo. El adecuado funcionamiento tiroideo, tanto materno como fetal, juegan un rol fundamental para la normal evolución del embarazo y del desarrollo neuropsicointelectual del feto, ya que una disminución aún leve de la función tiroidea en la primera mitad del embarazo puede tener secuelas a largo plazo. Las hormonas tiroideas son fundamentales para el normal desarrollo del SNC y del cerebro fetal. Además de las complicaciones fetales, las pacientes hipotiroideas tienen mayores complicaciones en el embarazo tales como aborto, parto prematuro, retardo del crecimiento intrauterino y bajo peso al nacer. Sería ideal que la paciente hipotiroidea programe su embarazo, se halle adecuadamente tratada y con un control estricto durante el embarazo. Si bien no hay consenso para el screnning de rutina, hay grupos que postulan la utilidad de incluir un dosaje de TSH y ATPO en el primer trimestre del embarazo. El diagnóstico precoz y su adecuado tratamiento evitarán complicaciones muchas veces irreversibles en el embarazo y en el desarrollo neurológico fetal.

Splicing variants impact in thyroid normal physiology and pathological conditions / Variantes de splicing e seu impacto em condições fisiológicas e patológicas da tireoide

RNA splicing is an essential, precisely regulated process that occurs after gene transcription and before mRNA translation, in which introns may be removed and exons, retained. Variability in splicing patterns is a major source of protein diversity from the genome and function to generate a tremendously diverse proteome from a relatively small number of genes. Changes in splice site choice can determine different effects on the encoded protein. Small changes in peptide sequence can alter ligand binding, enzymatic activity, allosteric regulation, or protein localization. Errors in splicing regulation have been implicated in a number of different disease states. This study reviewed the mechanisms of splicing and their repercussion in endocrinology, emphasizing its importance in some thyroid physiological and pathological conditions.

Após a transcrição genética e antes da tradução do mRNA, ocorre o splicing do RNA, que consiste em um processo essencial, precisamente regulado, por meio do qual podem ocorrer excisões de íntrons e retenções de éxons. A variabilidade dos padrões de splicing é a principal fonte de diversidade de proteínas geradas por um pequeno número de genes. Alterações na escolha do sítio de splicing podem determinar efeitos diferentes nas proteínas codificadas. Pequenas alterações na sequência peptídica podem alterar o seu sítio de ligação de substratos, sua atividade enzimática, a regulação alostérica ou a localização proteica. Erros na regulação do splicing têm sido implicados em grande número de doenças. Nessa revisão, foram descritos os mecanismos de splicing enfatizando sua importância em algumas condições fisiológicas e patológicas envolvendo a tireoide.

Tiroides y climaterio / Thyroid gland in the climacteric

Durante el climaterio, las enfermedades tiroideas constituyen una preocupación creciente, esto se debe a la mayor prevalencia de patología tiro idea observada en esta etapa de la vida. Para comprender mejor los trastornos tiroideos durante el climaterio se efectúa una revisión de la fisiopatología de la glándula tiroidea para posteriormente describir los trastornos más frecuentes en este período, su etiopatogenia manifestaciones clínicas y conducta terapéutica recomendada.

During the climacterium, thyroid diseases are a growing concern, this is due to the high prevalence of thyroid disease observed in this stage of life. In this article, the author reviewed the pathophysiology of the thyroid gland and then describe the most common thyroid disorders in this period, its pathogenesis, clinical and therapeutic recommended.

The Relationship between Thyroid Function and the Risk Factors of Cardiovascular Disease at Female Medical Checkups / 대한진단검사의학회지

BACKGROUND: Thyroid hormones play an important role in regulating lipid and glucose metabolism. Thus this study was conducted to investigate the relationship between the thyroid hormone (FT4) or thyroid stimulating hormone (TSH) and the cardiovascular risk factors and metabolic syndrome in the individuals with subclinical thyroid dysfunction. METHODS: The female health examinee with normal range of FT4 were classified into three groups according to the level of TSH; euthyroid group (n=4,410), subclinical hypothyroidism group (n=438) and subclinical hyperthyroidism group (n=66). Age, blood pressure, BMI, fasting glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride, lipoprotein(a), and high-sensitivity C-reactive protein (hsCRP) levels of serum specimens were compared among the groups and association of FT4 or TSH with these parameters. RESULTS: Fasting glucose was significantly higher in subclinical hyperthyroidism than in euthyroid and subclinical hypothyroidism groups (P=0.031), and total cholesterol was higher in subclinical hypothyroidism than in subclinical hyperthyroidism (P=0.011). But the other factors showed no difference among the groups. The level of TSH increased as triglyceride increased, while FT4 decreased as BMI or triglyceride increased. The FT4 also lowered when fasting glucose was above 126 mg/dL. TSH was not related with the metabolic syndrome, but the possibility of the syndrome was 1.3 times higher in the lowest quartile of the normal range of FT4 than in its highest quartile. CONCLUSIONS: For the interpretation of FT4, its reference interval needs to be divided into 4 quartiles, which can be used as one of the predicting factors of the metabolic syndrome.

Valores normales de captación de 131Yodo de 2 y 24 horas / Normal 131Iodine uptake values at 2 ano 24 hours

Background: Radiolabeled iodine uptake is a useful tool in the study of thyroid diseases. Aim: To obtain normal values for 131 Iodine thyroid uptake in healthy volunteers. Material and methods: A total of 105 subjects were included (52 males and 53 females), with a mean age of 45 years (range: 20 to 68, evenly distributed in decades). A questionnaire was applied and a clinical examination was performed to rule out endocrine diseases. Serum TSH and anti-thyroperoxidase antibodies were also measured. The oral 131I dose was 5-10 fiCi, and a Thyrad equipment was used for measurements at 2 and 24 h. Results: Mean global iodine uptake was 5.5 percent±1.8 percent (range: 2.3-12.0) at 2 h and 16.2±4.8 percent (range: 6.5-30.1) at 24 h. The values at 2 h among women and men were 6.0±1.8 and 4.9±1.6 percent, respectively, (p <0.02). At 24 h, the figures were 17.3±4.5 and 15.0±4.9 percent, respectively (p =0.01). Compared to their younger counterparts, radioactive iodine uptake was lower among volunteers older than 40 years, at 2 h (5.0±1.7 and 6.0±1.8, respectively, p <0.02) and at 24 h (14.9±4.4 and 17.6±4.9 percent, respectively, p <0.01). Conclusions: Normal thyroid uptake values in adults are influenced bygender and age. Normal thyroid iodine uptake values are slightly higher in females. Iodine thyroid uptake values decrease slightly in subjects aged more than 40years.

Tireoideopatias e gravidez / Diseases of thyroids and pregnancy

As doenças da tireóide têm mais prevalência no sexo feminino e, possivelmente, são secundárias aos efeitos dos esteróides sexuais no sistema imunológico. Daí advém à importância do esclarecimento das tireoidopatias e das maneiras de diagnósticá-las precocemente, a tempo de interferir em seu ciclo patogênico e evitar a ocorrência de danos materno-fetais. É necessário discernir entre o patogênico e as adaptações fisiológicas da gestação, estando necessariamente entre as doenças de rastreamento obrigatório nesse período. Hipotireoidismo é doença bastante freqüente em nosso meio, sendo de origem imunológica ou pela deficiência de iodo. Na gestação, é freqüentemente causado por tireoidite auto-imune ou por destruição da glândula. A doença de Graves é a causa mais freqüente de hipertireoidismo durante e fora do período gestacional. Contudo, apesar de apresentar menos prevalência em gestantes, seus efeitos são graves caso não diagnosticado e tratado em tempo hábil. A tireoidite pós-parto é mais comum em mulheres que têm concentração elevada de anticorpo antiTPO e apresenta gênese auto-imune, sendo influenciada pelo ciclo gravídico-puerperal. A presença de nódulos benignos, malignos e o câncer de tireóide ainda apresentam relação a ser esclarecida com o período gravídico.

The thyroid's diseases have greater prevalence in the female sex and, possibly, they are secondary to the effects of the sexual steroids in the immunological system. From there comes the importance of the clarification of the thyroid's diseases and its precocious diagnosis, in time to intervene in its pathological cycle and prevent damages for the embryo or for the mother. It is necessary to discern between the gestation pathological and physiological adaptations, the thyroid diseases being necessarity among the illnesses of obligatory tracking in this period. Hypothyroidism is frequent enough, due to its immunological origins of iodine deficiency. During gestation it is frequently caused by autoimmunity thyroiditis or gland destruction. Graves' disease is the hyperthyroidism most frequent cause during pregnancy of not. However, although its minor prevalence in pregnancy, its effects might be serious if it is not diagnosed and treated in time. Thyroiditis after-childbirth is more common in women who have high TPO antibodies concentration and presente autoimmunity origin, being influenced by the pregnancy-puerperal cycle. The presence of any kind of nodules and thyroid cancer still present relation with the pregnancy period to be clarified.

Efeito da inibição da lactação, três dias antes do desmame, sobre a regulação do metabolismo, ingestão alimentar e função tireóidea e cardiovascular, na prole adulta / Effect of lactation inhibition, three days before weaning, on regulation of metabolism, food intake and thyroid and cardiovascular function in adult offspring

Anteriormente, observamos que o bloqueio da produção de leite ao final da lactação pelo uso de um agonista dopaminérgico inibidor de prolactina, a bromocriptina (BRO), causou uma desnutrição moderada da prole e programou um sobrepeso, embora sem alteração de consumo alimentar, e hipotireoidismo na idade adulta. Assim, estudamos se ocorre programação do efeito central da leptina, de parâmetros da Síndrome Metabólica, além de melhor investigar o distúrbio da tireóide e enzimas dependentes de seus hormônios, na prole adulta, cujas mães receberam BRO (1mg/dia) nos 3 dias finais da lactação. Aos 180 dias de vida, a prole BRO apresentou maior conteúdo de gordura (total:+41 porcento, visceral:+20 porcento, subcutânea:+3x) e proteína corporal (+25 porcento), assim como menor conteúdo água (-4 porcento) e cinzas (-40 porcento) totais. Verificamos menor teor de cinzas (-6 porcento) e cálcio (-8 porcento) no fêmur. Estes ratos mostraram-se resistentes ao efeito anorexigênico da leptina, embora sem alterar a expressão de sua via de sinalização no hipotálamo; acreditamos que a resistência a injeção aguda de leptina possa estar relacionada à modificações nos mecanismos de fosforilação ou ainda à prejuízos em seu transporte pela barreira hemato-encefálica. Os ratos BRO são hiperglicêmicos (+16 porcento), resistentes à insulina (conforme índice HOMA IR, IRI e hipoadiponectinemia), além de exibirem hipercolesterolemia (+30 porcento), hipertrigliceridemia (+49 porcento), maior VLDL (+46 porcento), maior LDL (+104 porcento) e menor HDL (-28 porcento). Não apresentaram alteração de catecolaminas adrenais total, pressão arterial e freqüência cardíaca. Quanto à avaliação da função tireóidea, detectamos resposta hipofisária normal ao estímulo in vitro com TRH e a inibição com leptina, menor captação tireóidea de 125 (-41 porcento), atividades D2 hipofisária (-51 porcento) e GPDm (fígado: -55 porcento, TAM: -48 porcento)...

Previously, we observed that milk production blockade at the end of lactation using bomocriptine (BRO), a dopaminergic agonist that inhibits prolactin, cause undernutrition in the pups and programmes overweight without changes in food intake and hypothyroidism in the adult offsprings. So, here, we investigate the leptin central effect, metabolic syndrome parameters, and the disturbance of thyroid and thyroid hormones dependent enzymes, in adult animals whose mothers received BRO (1mg/day) in the last three days of lactation. At 180th day, BRO animals shows higher body fat mass (total: +41 percent, visceral: +20 percent and subcutaneous: +3x) and protein (+25 percent), lower content of water (-4 percent) and ash (-40 percent). The bone showed lower ash (-6 percent) and calcium (-8 percent) content BRO animals showed central leptin resistance, with no changes in the expression of proteins from the signalling pathway in the hypothalamus; suggesting defects on the phosphorilation of these proteins of impairment in the leptin transport by the blood-brain barrier. The BRO animals have higher glycaemia (+16 percent), insulin resistance (as shown by higher IRI and lower adiponectin), hypercholesterolemia (+30 percent), hypertriglyceridaemia (+49 percent), higher VLDL (+46 percent), LDL (+104 percent) and lower HDL (-28 percent) cholesterol. The animals showed higher relative catecholamines adrenal content, but normal blood pressure and heart rate. We observed normal pituitary response to in vitro TRH stimulation and leptin inhibition, lower 125 thyroid uptake (-41 percent), pituitary D2 activity (-51 percent) and mGPD (liver: -55 percent, BAT: -48 percent). All data indicate that neonatal undernutrition caused by maternal hypoprolactinaemia at the end of lactation programmes obesity, leptin and insulin resistances, hyperglycaemia and dyslipidemia, compatible with metabolic syndrome development. The hypothyroidism is functional and tertiary...

O papel dos hormônios tireoidianos na função testicular: [revisão] / Thyroid hormones and testicular function: [review]

Os hormônios tireoidianos são essenciais para o crescimento, desenvolvimento e metabolismo. O pró-hormônio tiroxina (T4) é sintetizado e secretado pela glândula tireóide junto com uma pequena quantidade do hormônio ativo, a triiodotironina (T3). A conversão de T4 em T3 ocorre na periferia através da atividade das iodotironinas desiodases tipo 1 e tipo 2. Os efeitos biológicos dos hormônios tireoidianos são mediados pela interação do hormônio metabolicamente ativo (T3) com transportadores de membrana e receptores nucleares, resultando em ativação da transcrição gênica. Classicamente as gônadas eram consideradas refratárias aos hormônios tireoidianos. Estudos recentes, no entanto, têm demonstrado que o hormônio da tireóide desempenha um papel crítico no aparelho reprodutor, não somente durante o período de desenvolvimento, mas também na vida adulta. Neste artigo apresentamos uma revisão sobre o papel desempenhado pelos hormônios tireoidianos sobre a função testicular.

Thyroid hormones play an important role in the growth, development, and metabolism of mammalian tissues. The prohormone thyroxine (T4) is synthesized and secreted by the thyroid gland together with a small amount of the active hormone, triiodothyronine (T3). The iodothyronine deiodinases types 1 and 2 catalize the peripheral T4 to T3 conversion. To exert its biological effects T3 interact with specific membrane transporters and nuclear receptors, thus activating gene transcription. Classically, male gonads were considered to be unresponsive to thyroid hormones. Recent studies, however, have shown that thyroid hormones have a critical role in the male reproductive system, not only during development, but also in adult life. Hence, we review and discuss the most recent advances in our understanding of thyroid hormone effects in male gonadal function.

Abuso de esteróides anabolizantes e seu impacto sobre a função tireóidea: [revisão] / Abuse of anabolic steroids and its impact on thyroid function: [review]

A utilização de esteróides anabolizantes por indivíduos que desejam aumentar sua performance física, ou simplesmente para fins estéticos, tem atingido índices alarmantes nas últimas três décadas. Além dos efeitos desejados, uma infinidade de efeitos colaterais já foi bem descrita na literatura, como vários tipos de câncer, ginecomastia, peliosis hepatis, insuficiência renal, virilização, dentre outros. Sobre a função tireóidea, o efeito mais pronunciado em seres humanos é a diminuição da TBG, com conseqüente diminuição sérica de T3 e T4 totais, dependendo, porém, da susceptibilidade da molécula à aromatização e conseqüente transformação em estrógeno. Em ratos, o tratamento com esteróides anabolizantes altera a metabolização periférica dos hormônios tireóideos e também parece causar importante efeito proliferativo sobre as células tireóideas. Assim, o presente artigo visa rever os dados publicados acerca dos efeitos de doses suprafisiológicas de esteróides anabolizantes sobre a função tireóidea, reforçando o perigo que a utilização indiscriminada dessas drogas pode causar à saúde.

The use of anabolic steroids to increase physical performance and for aesthetic ends has reached alarming indices in the last three decades. Besides the desired actions, several collateral effects have been described in the literature, such as the development of some types of cancer, ginecomasty, peliosis hepatis, renal insufficiency, virilization, amongst others. The most proeminent effect on human thyroid function is the reduction of thyroxine binding globulin (TBG), with consequent reductions of total serum T3 and T4, depending however on the susceptibility of the drug to aromatization and subsequent transformation into estrogen. In rats, anabolic steroids also act in the peripheral metabolism of thyroid hormones and seem to exert an important proliferative effect on thyroid cells. Thus, the aim of the present paper is to review data on the effect of supraphysiological doses of anabolic steroids on thyroid function, showing the danger that indiscriminate use of these drugs can cause to health.

Achados ultra-sonográficos na tireoidite / Ultrasound findings in thyroiditis

OBJETIVO: Avaliar os aspectos ultra-sonográficos da glândula tireóide em pacientes portadores de tireoidites. MATERIAIS E MÉTODOS: Num período de nove meses, foram estudados 38 pacientes atendidos no Serviço de Ultra-sonografia do Instituto de Radiologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, com diagnóstico prévio de tireoidite. Trinta e seis deles eram do sexo feminino, cujas idades variaram entre 17 e 78 anos. As variáveis observadas e estudadas foram: o volume glandular, a ecogenicidade e a ecotextura, e a presença de linfonodos na cadeia VI cervical (pré-traqueal, o sítio de drenagem linfática preferencial da tireóide) e suas dimensões. RESULTADOS: Treze pacientes apresentavam bócio. A análise ao ultra-som mostrou que 37 das 38 glândulas apresentavam ecotextura heterogênea com hipoecogenicidade difusa. Todos os pacientes apresentavam alterações nos exames laboratoriais compatíveis com tireoidites. Foram encontrados linfonodos na cadeia cervical VI (pré-traqueal) em 28 pacientes, todos de aspecto reacional. Destes, dez foram submetidos a punção aspirativa por agulha fina e o resultado citológico foi de reação inflamatória. Não foram encontrados casos de tireoidites focais que pudessem simular nódulos. CONCLUSÃO: Podemos inferir que para auxiliar no diagnóstico das tireoidites os achados ultra-sonográficos de heterogeneidade e hipoecogenicidade glandular, associados aos linfonodos na cadeia cervical VI, são de grande importância quando correlacionados aos exames clínicos e laboratoriais.

OBJECTIVE: The aim of this study was to evaluate sonographic features of thyroid gland in patients with thyroiditis. MATERIALS AND METHODS: During a nine-month period, 38 patients previously diagnosed with thyroiditis by the Ultrasound Unit of "Instituto de Radiologia da Faculdade de Medicina da Universidade de São Paulo", São Paulo, SP, Brazil, were studied. Thirteen-six of these patients were women in the age range between 17 and 78 years. The following variables were observed and studied: thyroid volume, echogenicity, echotexture, and the presence of level VI chain lymph nodes (pre-tracheal, the preferential site of thyroid drainage), besides the gland dimensions. RESULTS: Thirteen patients had goiter; 37 of 38 thyroid glands presented heterogeneous echotexture and diffuse hypoechogenicity. Thyroiditis was diagnosed by laboratory tests in all patients. Level VI chain (pre-tracheal) lymph nodes were observed in 28 cases, all of them with reactional features. Of these cases, ten patients were submitted to fine needle aspiration biopsy, and the cytological result indicated inflammatory reaction. No case of nodule-simulating focal thyroiditis was found. CONCLUSION: The thyroid gland sonographic hypoechogenicity and heterogeneity, in association with the presence of cervical chain lymph nodes, constitute findings of great importance in the diagnosis of thyroiditis when correlated with clinical and laboratory tests findings.

Hipotiroidismo neonatal: fisiopatogenia, aspectos moleculares, metabólicos y clínicos / Neonatal hypothyroidism: Pathophysiogenic, molecular and clinical aspects

This review provides an updated summary on both the clinical and diagnostic aspects of neonatal hypothyroidism (NeH); as well as on the molecular and pathophysiologic processes known to be involved in the installment of this important hormonal deficiency. Current information regarding its etiology and pathogenesis has allowed classigying NeH in three major groups: endemic, transient, and sporadic hypothyroidism. The later corresponds to congenital hypothyroidism and encompasses a broad spectrum of hereditary disorders causing hypothyroidism in newborns and young children. These congenital disorders include hypothalamic-pituitary or thyroid dysgenesis and/or dyshormonogenesis, as well as hyporesponsiveness or resistance to either TRH, TSH or to thyroid hormones. The introduction of national screening programs for NeH have overcome the difficulties in the early diagnosis thus helping to prevent its serious and irreversible consequences on intellectual and physical development. Concomitantly, an increase in the need for complementary etiologic and molecular diagnosis has risen. The current capability to perform a fine and precise diagnose is crucial both for treatment of the affected infant and for genetic counseling of the family. Although incomplete, available epidemiological information in Mexico indicates that NeH prevalence can be as high as twice that in other developed world countries. On these bases, national public health policies and epidemiological surveyance must be strengthen not only to identify, diagnose and timely treat, but to prevent and eradicate endemic NeH.

Este trabajo revisa algunos aspectos del conocimiento actual sobre la fisiopatogenia, los hallazgos clínicos y el diagnóstico bioquímico y molecular del hipotiroidismo neonatal (HNe). El término HNe denota un conjunto de entidades clínicamente pleomórficas, que invariablemente cursan con una disminución en el aporte; o bien, en la disponibilidad celular y/o en la respuesta a las hormonas tiroideas (HT) durante la etapa perinatal. Las HT o yodotironinas son indispensables para la morfogénesis y maduración funcional normal de prácticamente todos los tejidos en el organismo, y su participación es crucial en el caso del sistema nervioso. La información actual permite realizar una clasificación del HNe tanto en términos etio y fisiopatogénicos, como en el contexto del substrato genético que los determina. Así, se reconocen tres grandes tipos de HNe: el endémico, el transitorio y el esporádico. Este último grupo de HNe incluye los defectos hipotálamo-hipofisiarios, los trastornos ontogenéticos o disgenesias tiroideas, la resistencia periférica a las HT y las dishormonogénesis. Por otra parte, en la comunidad internacional existe una creciente preocupación por la contaminación ambiental debida a órgano-halógenos antropogénicos. Estos compuestos han mostrado su potencial como agentes distiroideos en animales de experimentación y en algunos estudios clínicos. En México, tanto la distribución geográfica y prevalencia del HNe, como la deficiencia de yodo y otros micronutrimentos en la dieta, se han analizado de manera esporádica y no sistemática. Aunque incompleta, la información disponible sugiere que en nuestro país la prevalencia de HNe es sensiblemente mayor que la reportada mundialmente. Contar con información completa y confiable acerca de estos aspectos no es trivial, puesto que su conocimiento permitirá establecer políticas razonadas de salud pública para identificar, diagnosticar y tratar oportunamente el padecimiento; así como para prevenir y erradicar el HNe endémico.

Adaptive changes in thyroid function of female rats fed a high-fat and low-protein diet during gestation and lactation

The percent of lipids in the western diet has been continuously increasing in the last decades and is associated with a decrease in the proportion of protein intake. Recently, we demonstrated that protein malnutrition during lactation is associated with lower body weight and thyroid hypofunction in female rats and their offspring. Our objective in the present study was to determine if a high-fat and low-protein diet was associated with similar changes. Three-month-old female Wistar rats were randomly assigned to one of the following groups with 8 animals each: high-fat and low-protein (40% lipid, 5% protein, and 55% carbohydrate of the total energy content) from the 3rd week of gestation to the end of lactation; control group - standard diet (11% lipid, 23% protein, and 66% carbohydrate of the total energy content). Food consumption and body weight were monitored daily. Serum thyrotropin and thyroid hormone concentrations were determined by specific radioimmunoassay at the end of lactation. Animals receiving high-fat and low-protein diet had a significantly lower body weight (13.9% at weaning, P < 0.05) and serum albumin (25%, P < 0.05) and thyrotropin (26.2%, P < 0.01) concentrations, and a higher serum triiodothyronine concentration (74%, P < 0.005) and 131I-thyroid uptake (77%, P < 0.005). These data show that a high-fat and low-protein diet can promote maternal thyroid hyperfunction that differs from the thyroid hypofunction observed in dams fed a low-protein diet, a phenomenon that can be of adaptive importance for pup nurturing.