Factores clínicos y bioquímicos asociados con la tirotropina en embarazadas aparentemente sanas / Clinical and biochemical factors associated with thyrotropin in seemingly healthy pregnant women

Introducción: Los valores de tirotropina (TSH) pueden modificarse marcadamente durante el embarazo, en relación con diversos factores clínicos y bioquímicos. Objetivo: Identificar los factores clínicos y bioquímicos asociados con la tirotropina en embarazadas aparentemente sanas. Métodos: Estudio descriptivo, transversal, con 247 gestantes aparentemente sanas del municipio Plaza de la Revolución., en el periodo comprendido de septiembre de 2015 a enero de 2019. Variables analizadas: edad materna y gestacional, trimestre del embarazo, color de la piel, paridad, hábito de fumar, antecedentes familiares de enfermedad tiroidea (APF), consumo de suplementos con yodo, índice de masa corporal (IMC), presencia de bocio al examen físico, TSH, tiroxina total (T4t) y libre (T4l), triyodotironina total (T3t) y libre (T3l), gonadotropina coriónica (hCG), anticuerpos contra la peroxidasa tiroidea (AcTPO) y la tiroglobulina (AcTg) y yoduria. Resultados: La TSH (1,66 ± 0,91mUI/L) tuvo una asociación negativa con la edad materna (r = -0,17; p = 0,008), la paridad (nulíparas 1,80 ± 0,90 mUI/L, multíparas 1,45 ± 0,89 mUI/L; p = 0,003), los APF (positivos 1,56 ± 0,91 mUI/L, negativos 1,81 ± 0,89 mUI/L; p = 0,03), la T4t (r = -0,15; p = 0,02), la T4l (r = -0,23; p = 0,000) y la hCG (r = -0,52; p = 0,001). Mostraron una relación directa la edad gestacional (r = 0,25; p = 0,000) y el uso de suplementos yodados (consumo 1,96 ± 0,72mUI/L, no consumo 1,62 ± 0,93 mUI/L; p = 0,03). Conclusiones: La tirotropina presenta una relación inversa con la edad materna, la paridad, los antecedentes familiares de enfermedad tiroidea, la T4 total y libre, y la gonadotropina coriónica, y una relación directa con la edad gestacional y el consumo de suplementos con yodo(AU)

Introduction: Thyrotropin (TSH) values can be sharply modified during pregnancy, in relation to various clinical and biochemical factors. Objective: Identify clinical and biochemical factors associated with thyrotropin in seemingly healthy pregnant women. Methods: Descriptive, cross-sectional study with 247 seemingly healthy pregnant women from Plaza de la Revolution municipality in the period from September 2015 to January 2019. Variables analyzed: maternal and gestational age, trimester of pregnancy, skin color, pregnancies, smoking habit, family history of thyroid disease (APF), consumption of iodine supplements, body mass index (BMI), presence of goiter to physical examination, TSH, total and free (T4l) thyroxine (T4t), total (T3t) and free (T3l) triiodothyronine, chorionic gonadotropin (hCG), antibodies against thyroid peroxidase (AcTPO) and thyroglobulin (AcTg) and urinary iodine. Results: TSH (1.66 ± 0.91mUI/L) had a negative association with maternal age (r = -0.17; p x 0.008), pregnancy (nulliparas 1.80 ± 0.90 mUI/L, 1.45 ± 0.89 mUI/L; p x 0.003), APF (positive 1.56 ± 0.91 mUI/L, negative 1.81 ± 0.89 mUI/L; p x 0.03), the T4t (r = -0.15; p s 0.02), the T4l (r = -0.23; p x 0.000) and the hCG (r = -0.52; p x 0.001). They showed a direct relationship with gestational age (r x 0.25; p x 0.000) and the use of iodine supplements (consumption 1.96 ± 0.72mUI/L, not consumption 1.62 ± 0.93 mUI/L; p x 0.03). Conclusions: Thyrotropin has an inverse relationship with maternal age, pregnancies, family history of thyroid disease, total and free T4, and chorionic gonadotropin, and a direct relationship with gestational age and consumption of iodine supplements(AU)

Uso de tirotropina recombinante humana (rhTSH) en rastreo corporal total con radioyodo (131 I), en pacientes con cáncer diferenciado de tiroides intolerante a la suspención de levotiroxina y con sospecha de recurrencia / Use of recombinant human thyrotropin (rhTSH) in total body tracing with radioiodine (131 I) in patients with differentiated thyroid cancer intolerant to levothyroxine suspension and with suspected recurrence

INTRODUCCIÓN: Antecedentes: El presente dictamen expone la evaluación de tecnología del uso de la tirotropina alfa o tirotropina recombinante humana (rhTSH, por su nombre en inglés) como preparación para realizar un rastreo corporal total (RCT) con radioyodo. Esta evaluación específica para pacientes con sospecha de recidiva de cáncer de tiroides diferenciado, en los que el retiro del tratamiento con levotiroxina no es tolerado. Aspectos Generales: El cáncer de tiroides es el tipo más común de cáncer endocrino y representa menos del 1% de todos los tumores humanos. La incidencia anula de este cáncer varia considerablemente por área geográfica, edad y sexo. Tecnología Sanitaria de Interés: En pacientes en seguimiento posterior al tratamiento de cáncer diferenciado de tiroides y en los que se sospecha recidiva del mismo se sugiere la realización pruebas diagnósticas como el RCT con radioyodo. Para realizar esta prueba en los pacientes mencionados es necesario lograr una elevación de la TSH sérica y promover la captación del marcador en el tejido facilitando su identificación. La tirotropina alfa o rhTSH es una glicoproteína heterodimérica con propriedades bioquíimicas comparables al TSH pituiario humano. La unión de esta sustancia con receptores de TSH en las células epiteliales tiroideas o en tejido tiroideo canceroso diferenciado estimula en éstas la captación de yodo y organización, así como la síntesis y secreción de Tg. METODOLOGÍA: Estrategia de Búsqueda: Se realizó una estrategia de búsqueda sistemática de la evidencia científica con respecto al uso del rhTSH para realizar un rastreo corporal total (RCT) con radioyodo para la detección de cáncer diferenciado de tiroides, intolerante la suspensión de levotiroxina, con sospecha de recurrencia. Se ralizó una búsqueda de estudios en humanos que mostraron evidencia científica en relación a los puntos desarrollados en la pregunta PICO. Se dio preferencia a estudios de tipo meta-análisis, revisiones sistemáticas de ensayos clínicos aleatorizados y ensayos clínicos aleatorizados; así como a guías de práctica clínica de grupos o instituciones relevantes al tema analizado. la bibliografia usada en los artículos seleccionados, así como la inforamación disponible por entes reguladores y normativos como la Food and Drug Administration ( Administración de Drogas y Alimentos, o FDA por sus siglas en inglés) de los Estados Unidos y, a nivel nacional, la DIGEMID. RESULTADOS: Sinopsis de la Evidencia: Se realizó la búsqueda y revisión de la evidencia científica actual para la evaluación del rhTSH para realizar un rastreo corporal total (RCT) con radioyodo para la detección de cáncer diferenciado de tiroides, itolerante la suspensión de levotiroxina, con sospecha de recurrencia. Se presenta la información encontrada de acuerdo al tipo de evidencia revisada. CONCLUSIONES: La evidencia encontrada a la fecha (mayo 2016) indica que el rhTSH puede ser utilizado como una opción alternativa a la suspensión de tratamiento reemplazo hormonal tiroideo como preparación para un RCT con radioyodo en los pacientes descritos. Esta opción no ha demostrado un benefício en la precisión diagnóstica del RCT, presentado solo un benefício de corto plazo al disminuir los efectos adversos asociados a la realización de la prueba. Así, si bien la evidencia no es contundente con respecto al uso la rhTSH como una primera opción para la preparación para un rastreo corporal total con radioyodo en los pacientes descritos, esta es útil y corresponde a la única alternativa disponible actualmente como prueba diagnóstica en el caso de los pacientes que no puedan suspender el tratamiento hormonal por falta de tolerancia, definida por el médico tratante, u obras causas médicas que contraindioquen el estado hipotiroideo. El Instituto de Evaluación de Tecnologías en Salud e Investigación, aprueba el uso de la tirotropina recombinante humana (rhTSH) como preparación para un rastreo corporal total con radioyodo en pacientes con cáncer diferenciado de tiroides posterior al tratamiento, en los que se sospecha recurrencia y que no puedan suspender el tratamiento hormonal por falta de tolerancia, definida por el médico tratante, u otras causas médicas que contraindiquen el estado hipotiroideo.

Radioiodine plus recombinant human thyrotropin do not cause acute airway compression and are effective in reducing multinodular goiter

Recombinant human thyrotropin (rhTSH) reduces the activity of radioiodine required to treat multinodular goiter (MNG), but acute airway compression can be a life-threatening complication. In this prospective, randomized, double-blind, placebo-controlled study, we assessed the efficacy and safety (including airway compression) of different doses of rhTSH associated with a fixed activity of 131I for treating MNG. Euthyroid patients with MNG (69.3 ± 62.0 mL, 20 females, 2 males, 64 ± 7 years) received 0.1 mg (group I, N = 8) or 0.01 mg (group II, N = 6) rhTSH or placebo (group III, N = 8), 24 h before 1.11 GBq 131I. Radioactive iodine uptake was determined at baseline and 24 h after rhTSH and thyroid volume (TV, baseline and 6 and 12 months after treatment) and tracheal cross-sectional area (TCA, baseline and 2, 7, 180, and 360 days after rhTSH) were determined by magnetic resonance; antithyroid antibodies and thyroid hormones were determined at frequent intervals. After 6 months, TV decreased significantly in groups I (28.5 ± 17.6 percent) and II (21.6 ± 17.8 percent), but not in group III (2.7 ± 15.3 percent). After 12 months, TV decreased significantly in groups I (36.7 ± 18.1 percent) and II (37.4 ± 27.1 percent), but not in group III (19.0 ± 24.3 percent). No significant changes in TCA were observed. T3 and free T4 increased transiently during the first month. After 12 months, 7 patients were hypothyroid (N = 3 in group I and N = 2 in groups II and III). rhTSH plus a 1.11-GBq fixed 131I activity did not cause acute or chronic changes in TCA. After 6 and 12 months, TV reduction was more pronounced among patients treated with rhTSH plus 131I.

Area under the curve of TSH after levothyroxine withdrawal versus administration of recombinant human TSH (rhTSH): possible implications for tumor growth / Área sob a curva de TSH após suspensão da levotiroxina versus administração do TSH recombinante humano: possíveis implicações no crescimento tumoral

OBJECTIVE: The levothyroxine withdrawal (L-T4) for some weeks results in prolonged exposure to elevated TSH. In contrast, administration of recombinant human TSH (rhTSH) promotes a short period of hyperthyrotropinemia. The objective of this study was to compare the area under the curve (AUC) of TSH obtained after L-T4 withdrawal versus administration of rhTSH. METHODS: Thirty patients received 0.9 mg rhTSH for two consecutive days, and 64 were prepared by L-T4 withdrawal for four weeks, with the latter being reintroduced 48 hour after 131I. Measurement of TSH were performed before the first rhTSH ampoule; immediately before and seven and 14 days after 131I; before L-T4 withdrawal; and, weekly, up to two months after 131I. RESULTS: The AUC obtained after rhTSH was 4.6 times smaller than that obtained after L-T4 withdrawal (532 versus 2,423 mIU/L per day). It should be emphasized that, on average, in the latter group, 58.5 percent of the AUC corresponded to the period after reintroduction of hormone therapy. CONCLUSIONS: Surprising difference in the TSH AUC was demonstrated between rhTSH administration versus L-T4 withdrawal.

OBJETIVO: A suspensão de levotiroxina (L-T4) por algumas semanas resulta em exposição prolongada ao TSH elevado. Em contraste, a administração do TSH recombinante (rhTSH) promove um curto período de hipertirotropinemia. O objetivo deste estudo foi comparar a área sob a curva (do inglês "area under the curve", AUC) do TSH obtida após suspensão da L-T4 versus a administração do rhTSH. MÉTODOS: Trinta pacientes receberam 0,9 mg de rhTSH por dois dias consecutivos, e 64 foram preparados com suspensão da L-T4 por quatro semanas, com reintrodução dessa terapia 48 horas após o radioiodo. As medidas de TSH foram realizadas antes da primeira ampola de rhTSH; imediatamente antes e sete e 14 dias após o 131I; antes da suspensão da L-T4; e, semanalmente, até dois meses após o 131I. RESULTADOS: A AUC do TSH obtida após rhTSH foi 4,6 vezes menor do que a alcançada após suspensão da L-T4 (532 versus 2.423 mUI/L ao dia). Enfatiza-se que, em média, no último grupo, 58,5 por cento da AUC correspondeu ao período após a reintrodução da terapia hormonal. CONCLUSÕES: Surpreendente diferença na AUC do TSH foi demonstrada entre a administração do rhTSH versus suspensão da L-T4.

Protocol for thyroid remnant ablation after recombinant TSH in thyroid carcinoma / Protocolo para ablación de remanentes tiroideos luego de TSH recombinante en el cáncer diferenciado de tiroides

In some countries, in order to perform rhTSH-aided thyroid remnant ablation (TRA) after surgery, it is generally necessary to confirm that thyroidectomy has been almost complete. Otherwise, the nuclear medicine specialist will not administer a high radioiodine dose because it might be hazardous due to the possibility of thyroid remnant actinic thyroiditis. Considering this, it would be necessary to use two rhTSH kits (one for diagnostic purposes and the other one to administer the 131I dose). In this study, we used an alternative protocol for TRA with the use of one kit of rhTSH in twenty patients diagnosed with low risk papillary thyroid carcinoma. All patients had negative titers of anti-thyroglobulin antibodies. Successful thyroid remnant ablation was confirmed with an undetectable rhTSH stimulated thyroglobulin level (< 1 ng/ml) in all 20 patients between 8 to 12 months after radioiodine administration. The use of this protocol combining scintigraphy with the subsequent administration of a therapeutic dose following the administration of one kit of rhTSH would avoid the need of using 2 kits to perform the ablation and would decrease the costs associated with its use while significantly enhancing the quality of life of patients with thyroid cancer.

En algunos países, para realizar la ablación de los remanentes tiroideos con radioyodo después de la cirugía, generalmente se requiere confirmar que la tiroidectomía fue casi completa, ya que de otra manera el especialista en medicina nuclear no administrará una dosis elevada de radioyodo, considerando que esto puede ser dañino para el paciente debido a la posibilidad de generar una tiroiditis actínica. De acuerdo con esto, sería necesario administrar 2 kits de rhTSH (uno para diagnóstico y otro para la dosis de radioyodo). En este estudio, empleamos un protocolo alternativo para la ablación luego de la administración de un único kit (2 ampollas) de rhTSH en 20 pacientes con antecedentes de un carcinoma papilar de bajo riesgo. Todos los pacientes presentaban títulos negativos de anticuerpos anti-tiroglobulina. La ablación exitosa de remanente tiroideo se confirmó con un nivel no detectable de tiroglobulina (<1 ng/ml) al estímulo por rhTSH en los 20 pacientes, entre 8 a 12 meses luego de la ablación. El uso de este protocolo que combina la posibilidad de realizar un centellograma diagnóstico y la ablación luego del uso de un solo kit de rhTSH, facilita su empleo, disminuye los costos asociados, a la vez que permite una mejor calidad de vida de los pacientes con cáncer de tiroides.

Effect of 30 mCi radioiodine on multinodular goiter previously treated with recombinant human thyroid-stimulating hormone

Recombinant human thyroid-stimulating hormone (rhTSH) enhances 131I uptake, permitting a decrease in radiation for the treatment of multinodular goiter (MNG). Our objective was to evaluate the safety and efficacy of a single 0.1-mg dose of rhTSH, followed by 30 mCi 131I, in patients with MNG. Seventeen patients (15 females, 59.0 ± 13.1 years), who had never been submitted to 131I therapy, received a single 0.1-mg injection of rhTSH followed by 30 mCi 131I on the next day. Mean basal thyroid volume measured by computed tomography was 106.1 ± 64.4 mL. 131I 24-h uptake, TSH, free-T4, T3, thyroglobulin, anti-thyroid antibodies, and thyroid volume were evaluated at regular intervals of 12 months. Mean 131I 24-h uptake increased from 18.1 ± 9.7 to 49.6 ± 13.4 percent (P < 0.001), a median 2.6-fold increase (1.2 to 9.2). Peak hormonal levels were 10.86 ± 5.44 mU/L for TSH (a median 15.5-fold increase), 1.80 ± 0.48 ng/dL for free-T4, 204.61 ± 58.37 ng/dL for T3, and a median of 557.0 ng/mL for thyroglobulin. The adverse effects observed were hyperthyroidism (17.6 percent), painful thyroiditis (29.4 percent) and hypothyroidism (52.9 percent). Thyroid volume was reduced by 34.3 ± 14.3 percent after 6 months (P < 0.001) and by 46.0 ± 14.6 percent after 1 year (P < 0.001). Treatment of MNG with a single 0.1-mg dose of rhTSH, followed by a fixed amount of radioactivity of 131I, leads to an efficacious decrease in thyroid volume for the majority of the patients, with a moderate incidence of non-serious and readily treatable adverse effects.

Uso do TSH humano recombinante no câncer diferenciado de tireóide / Recombinant human TSH use in differentiated thyroid cancer

O seguimento imediato após tireoidectomia total (TT), em pacientes com câncer diferenciado de tireóide (CDT), tradicionalmente é feito com a ablação de remanescentes tireoidianos (RT) com 131I, na vigência de hipotireoidismo. O seguimento tardio do CDT inclui o uso de doses supressivas de T4, dosagem seriada da tireoglobulina (Tg), pesquisa de corpo inteiro (PCI) com 131I e ultra-sonografia (US) cervical. Nos últimos anos, tem-se mostrado que a ablação de RT com a ajuda do TSH recombinante humano (rhTSH) tem a mesma eficácia que a ablação de RT observada com a elevação endógena do TSH, mas sem os sintomas e piora de qualidade de vida descritos no hipotireoidismo. A dosagem da Tg estimulada com TSH endógeno ou exógeno, 9 a 12 meses após o tratamento inicial do CDT, associado à US cervical, pode identificar pacientes de baixo risco potencialmente curados de sua doença e nos quais a supressão do TSH não necessita ser tão intensa, evitando as complicações cardíacas e ósseas da tireotoxicose exógena prolongada. Finalmente, apesar de não existirem estudos randomizados que avaliem o papel do rhTSH no tratamento do CDT metastático, os resultados do tratamento combinado do rhTSH e 131I mostram um benefício clínico na maioria dos pacientes tratados.

Traditionally, the immediate treatment of patients with differentiated thyroid carcinoma (DTC) after total thyroidectomy (TT) is thyroid remnant ablation (TRA) with 131I, during hypothyroidism. Late follow-up of DCT includes suppressive doses of T4, serial measurements of thyroglobulin (Tg), whole body scan (WBS) with 131I and cervical ultrasound (US). In the last years, TRA with the aid of recombinant human TSH (rhTSH) has shown not only to avoid symptoms of hypothyroidism and a lower quality of life, but also to have the same efficacy as TRA during endogenous TSH elevation. Stimulated Tg with endogenous or exogenous TSH, 9 to 12 months after the initial treatment of DTC, associated with cervical US, is able to identify low-risk patients virtually cured of their disease, in whom TSH suppression does not need to be so strict, avoiding the heart and bone complications of prolonged exogenous thyrotoxicosis. Finally, in spite of the absence of randomized studies designed to evaluate the role of rhTSH in metastatic DTC disease, results of the combined treatment of rhTSH and 131I show a clinical benefit in the majority of treated patients.

Usefulness of recombinant human TSH aided radioiodine doses administered in patients with differentiated thyroid carcinoma

The published studies confirming the safety and efficacy of rhTSH for diagnostic purposes have ledto an increased interest in its use for preparation for radioiodine (RI) dose administration in patientswith recurrent or persistent differentiated thyroid carcinoma (DTC). In order to establish the efficacy of RItherapy after rhTSH, we have reviewed 39 rhTSH-aided radioiodine treatment in a series of 28 DTC patients.Patients were divided into two groups: GI (n=17), with previous thyroid bed uptake and undetectable thyroglobulin(Tg) levels under levothyroxine treatment and GII (n=11), with proven metastatic local or distant disease.Median follow-up after the first rhTSH-aided radioiodine treatment was 32 ± 13 months (range 8 to 54 months).Sixteen patients (94%) in GI were rendered disease free and one patient was shown to have persistent disease.In GII, the post therapy whole body scan showed pathological uptakes in all cases: in four patients in lungs, infour in mediastinum and in three in lateral neck. In two patients with mediastinum uptake, Tg levels wereundetectable after rhTSH. In the follow-up, two patients with lateral neck uptake were rendered disease free,four patients died (three due to thyroid cancer) and five out of the remaining patients have persistent disease. Inconclusion, rhTSH aided therapy was helpful to eliminate normal thyroid bed remnants in 16/17 (94%) patients(GI). rhTSH stimulated Tg was undetectable in two patients with mediastinal metastasis. We believe that rhTSHis a good alternative to levothyroxine withdrawal for the treatment of DTC with radioactive iodine, increasing thequality of life in these patients. Caution should be recommended in the follow-up of unselected DTC patientsonly with stimulated Tg levels.

Los estudios publicados que confirman la seguridad yeficacia de la TSH recombinante (rhTSH) llevaron a un incremento en el interés para su uso como adyuvanteterapéutico en el CDT (ablación o tratamiento de enfermedad metastática). Para evaluar la efectividad de laadministración de dosis terapéuticas de RI luego de la administración de rhTSH, realizamos un análisisretrospectivo en 28 pacientes con CDT que recibieron 39 dosis de RI. Los pacientes se dividieron en 2 grupos:GI (n=17) pacientes con captación en el lecho tiroideo y niveles indetectables de tiroglobulina (Tg) bajo tratamientosupresivo con levotiroxina y GII (n=11), pacientes con enfermedad metastática local o a distancia, previamentecomprobada. El seguimiento promedio luego de la primera dosis de RI fue de 32 ± 13 meses (rango 8 a 54meses). Dieciseis pacientes (94%) del GI fueron considerados libres de enfermedad y un paciente presentó unapersistencia local. En el GII, las captaciones patológicas fueron: en 4 pacientes en pulmones; en 4 en mediastinoy en 3 a nivel lateral cervical. Dos pacientes con captaciones mediastinales presentaron niveles indetectablesde Tg. En el seguimiento, dos pacientes con captaciones latero-cervicales se consideraron libres de enfermedad,cuatro pacientes murieron (tres debido al CDT avanzado) y cinco de los restantes tienen enfermedad persistente.En conclusión, la terapia con RI luego de rhTSH fue útil para ablacionar remanentes normales en el GI. Losniveles de Tg estimulados con rhTSH fueron indetectables en dos pacientes con metástasis mediastinales. Eluso de rhTSH parece ser una alternativa válida frente a la suspensión de la terapia hormonal en el tratamientode pacientes con CDT, incrementando la calidad de vida de estos pacientes.

Effects of thyrotropin-releasing hormone on urethral closure pressure in females with voiding dysfunction

To evaluate the effect of intravenous thyrotropin releasing hormone [TRH] on the urethral closure pressure [UCP]. Twenty-two female patients with either bladder outlet obstruction [BOO] or detrusor under activity were included in this study. They divided into two study and control groups randomly. Twelve patients in study group received 200 gr of TRH intravenously and patients in control group received intravenous normal saline as placebo. Standard urethral pressure profilometry was performed before injection and after injection at 5, 10, 20 and 30 minutes. Functional profile length [FPL], maximum urethral closure pressure [MUCP], and urethral closure pressure at the proximal quarter of the FPL [1/4 FLP] and at the distal quarter of FPL [3/4 FLP] were measured in both groups. The mean age of the study and control groups were 41.61 +/- 21.7 years and 43.59 +/- 19 years respectively .The study and control groups included 5 BOO and 6 detrusor under activity and 4 BOO and 5 detrusor under activity respectively. The mean peak flow rate was 5.69 +/- 8.4 ml/s in the study group and 6.31 +/- 81 ml/s in control group. There wasn't significant difference between two groups. Mean maximum urethral closure pressure demonstrated no significant difference in two groups before and after TRH injection, but a marked reduction in 3/4 UCP and 3/4 FPL in patients after TRH injection was seen. TRH injection significantly reduces the distal urethral pressure

Possible action of intracerebroventricular thyrotropin on Brobeck's hypothesis.

The effect of ICV administered TSH on Brobeck's thermostatic hypothesis was evaluated by recording chronological changes in electrical activity of precise loci (POA, VMN and CO) coupled by rectal temperature changes in dogs. The study revealed 1. TSH action on thermoregulation is biphasic in nature. 2. This action of TSH is not an independent act but depends on the reaction of satiety centre.

Responses of pre-optic area to intracerebroventricular thyroxine and thyrotropin in dog brain.

Electroencephalographic activity (EEG) of pre-optic area (POA) was recorded after intracerebroventricular (ICV) microinjection of thyroxine (T4) and thyrotropin (TSH) in conscious male dogs. Recordings were made for two hours following microinjections. Biphasic responses with increased amplitude were observed in both the treatments, but chronologically the responses obtained with T4 & TSH were opposite to each other.

Valor clínico da dosagem ultra-sensível de TSH na avaliaçäo da funçäo tiroideana

A concentraçäo sérica de TSH de 225 indivíduos normais e 348 pacientes portadores de diversas patologias tiroideanas foi analisada através de um Kit comercial imunorradiométrico (IRMA) ultra-sensível para dosagem deste hormônio (Med Lab/DPC). A sensibilidade do método foi de 0,10 micronU/ml. O valor médio detectado nos indivíduos normais foi 1,06 ñ 0,56, sendo que nessa populaçäo näo se detectou nenhum valor abaixo de 0,30 micronU/ml e nem acima de 3,5 micronU/ml. Quarenta e nove pacientes portadores de doença de Graves com tirotoxicose apresentaram valores abaixo de 0,10 micronU/ml. O mesmo aconteceu com oito pacientes portadores de nódulo autônomo de tiróide. Oitenta e três pacientes com doença de Graves, compensados clinicamente pelo uso de propiltioouracil (PTU), apresentaram valores de < 0,10-3,9 micronU/ml. Cento e vinte pacientes com hipotiroidismo primário, sem medicaçäo, apresentaram valores de 4,0-700 micronU/ml, enquanto que 49 pacientes recebendo l-tiroxina (T4) mostraram valores de < 0,10-10 micronU/ml. Quatorze pacientes portadores de bócio simples tratados com T4 apresentaram valores de < 0,10-0,50 micronU/ml, enquanto que 22 com carcinoma de tiróide, recebendo T4, mostraram valores de < 0,10-0,26 micronU/ml. A análise dos valores de TSH após estímulo com TRH mostrou nítida correlaçäo entre os valores basais e pós-estímulo. Pacientes com TSH basal superior a 4,0 micronU/ml apresentaram hiper-resposta ao TRH (>30 micronU/ml mostraram resposta máxima após TRH sempre inferior a 2,0 micronU/ml. Oito pacientes apresentando TSH basal indetectável responderam parcialmente ao TRH (<2,0 micronU/ml enquanto 15 näo apresentaram resposta detectável. Estes resultados, somados a larga experiência internacional com este método, indicam que a medida ultrasensivel do TSH pode ser considerada e, potencialmente pode se transformar no teste inicial de avaliaçäo em todas as situaçöes de suspeita de disfunçäo desta glândula