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OBJECTIVE: Compare two different strategies in newborn screening for congenital hypothyroidism, primary TSH in the umbilical cord blood (method 1) and primary T4 in blood collected from the heel in the 2nd day of life (method 2). METHODS: We compared both strategies in 10,000 newborns, measuring TSH by a sensitive immunofluorimetric assay and T4 by a radioimmunoassay. RESULTS: Both strategies detected all cases of hypothyroidism (4 cases, 1/2,500 newborns). The recalling index owing to insufficient amount of blood to perform the assays was zero in method 1 and 8.5% (850 newborns) in method 2. The recalling index for confirmation of the results was 0.06% (6 newborns) in method 1 and 2.25% (225 newborns) in method 2; when method 2 included supplementary TSH, the recalling index was reduced to 1.63% (163 newborns). CONCLUSION: Our data indicate the technical superiority of the umbilical cord blood compared to heel and primary TSH compared to primary T4 in the neonatal thyroid screening for congenital hypothyroidism.

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Objetivo. Comparar em recém-nascidos (RN) duas estratégias diferentes para o rastreamento do hipotiroidismo congênito (HC), a dosagem primária de TSH no sangue colhido do cordao umbilical (método 1) e a dosagem primária de T4 no sangue colhido por punçao de calcanhar no 2 dia de internaçao (método 2). Métodos. Os autores compararam as duas estratégias em 10.000 RN. Dosaram o TSH por método imunofluorimétrico sensível em papel de filtro e o T4 por radioimunoensaio em papel de filtro. A coleta de sangue do calcanhar foi realizada no 2 dia de vida. Resultados. Os dois programas diagnosticaram todos os casos de HC nos RN (4 casos, 1/2.500 RN). O índice de rechamada por coleta inadequada foi nulo no método 1 e de 8,5 por cento (850RN) no método 2. O índice de reconvocaçao para confirmaçao de resultados foi de 0,06 por cento (6RN) no método 1 e 2,25 por cento (225 RN) no método 2; quando este método incluía também a dosagem suplementar de TSH, o índice baixou para 1,63 por cento (163 RN). Conclusao. Os dados dos autores evidenciam a superioridade técnica da coleta de sangue a partir do cordao umbilical em relaçao à punçao de calcanhar, assim como da dosagem primária de TSH em relaçao à de T4, uma vez que apresentam índices muito menores de reconvocaçao.

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A one-step enzyme linked sandwich immunoassay using Silicone rods coated with rabbit anti-human thyroglobulin anti-Tg) immunoglobulin G (Fab') conjugated with beta-D-galactosidase was established for the measurement of thyroglobulin in human sera. The volume of serum needed for the assay was 2 mul The sensitivity of the assay was 1.52 amol/tube, corresponding to O.5 ng/ml. The precision was proven by coefficients of variation: intra-assay, 7.0 to 9.1 per cent: inter-assay, 5.3 to 7.4 per cent. The correlation between this EIA and RIA was O.91, p < O.O1.

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An enzymeimmunoassay (EIA) for H-TSH (human thyrotropin) in dried blood on filter paper using an anti-H-TSH conjugate with ß-D-galactosidase and tubes coated with an anti-H-TSH was performed fo the screening program for detection of congenital hypothyroidism. The blood volume needed in this assay was 8.7 µl. The precision was evaluated by coefficients of variance within and between assays: 11.86 percent and 14.36 percent for H-TSH levels of 18.5 µU/ml and 35 µU/ml. A good correlation was observed between H-TSH concentration measured by EIA and RIA (r=0.91)

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The immigration of Japanese people to Brazil began in 1908 with two major waves, from 1925 to 1940 and from 1952 to the 1960s. Brazil has the largest population (about 1,288,000) of Japanese origin outside Japan with varying age groups. A mortality study revealed that diabetes as an underlying cause of death was higher in the first-generation Japanese than in Japan (3.4 vs. 1.9 per 100,000 for men, and 7.2 vs. 1.9 for women). The self-reported prevalences of known diabetes in subjects aged 40 years or older were obtained by questionnaires from three sources. In six Japanese cultural associations in Säo Paulo city, the prevalences were 9.7% and 6.9% for the first generation (mean age 61.5 years) and for the second generation (mean age 40.0 years), respectively. Age-adjusted prevalences, according to the Brazilian population in the 1980 national census, were 6.9% and 8.1% for the first and second generations. According to a study carried out as a part of a socioeconomic census of the Japanese population in Brazil, the prevalences of diabetes were 7.4% and 5.2%, and the age-adjusted prevalences were 5.3% and 5.8% in the first and second generations, respectively. Another study carried out for employees of a bank, owned by Japanese-Brazilian community members, revealed crude prevalences of diabetes in the first and second generations of 7.1% and 4.2%, and age-adjusted prevalences of 7.3% and 8.2%, respectively. These data indicate an increased prevalence of diabetes in this population compared to Japan, suggesting the importance of environmental factors in the pathogenesis of diabetes.

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Amiodarone, a drug extensively used as an antiarrhythmic agent, contains 37% iodine and causes several thyroid abnormalities. The transplacental passage of amiodarone occurs with chronic therapy; we describe in this report the outcome of 9 pregnant women who used amiodarone (200 mg/day) for treatment of resistant tachycardia and the follow-up of their newborns. All women were clinically euthyroid at the 3rd trimester and showed expected values of thyroid hormones (mean +/- SD: total T4, 228 +/- 45 nmol/L; total T3, 4.0 +/- 0.65 nmol/L; TSH, 4.0 +/- 1.8 mU/L; negative thyroid antibodies). At birth all newborns were normal on routine examination with no goiter or corneal changes. T4 and TSH, measured on dried umbilical blood spots were normal or borderline-normal in 8 of 9 babies. Only 1 neonate presented clearly abnormal values of T4 and TSH (96 mU/L); on clinical grounds the baby was normal, without signs of hypothyroidism. At 1 month of life, T4 and TSH were normal. Follow-ups at 3, 6, and 12 months were normal. We conclude that is not necessary to discontinue treatment with amiodarone in pregnant women with resistant tachycardia, but it is imperative to evaluate the thyroid function of the newborn, since transient hypothyroidism may occur.

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The effect of intermittent mechanical ventilation and positive end-expiratory pressure on plasma antidiuretic hormone concentration was determined in 14 pentobarbital anesthetized dogs. The study was divided into a control period (spontaneous respiration), and two consecutive 30 and 60 min periods after the start of controlled respiration: Group I - intermittent positive breathing (IPPB); Group II - positive end-expiratory pressure (PEEP) with 5 cm H2O. A decrease in urinary flow (36.9%) was observed during end-expiratory pressure breathing. An increase in plasma antidiuretic hormone in group II from 4.5 +/- 2.4 to 24.6 +/- 16.0 pg/ml (P less than 0.01) was associated with a significant reduction of free water clearance from 1.2 +/- 0.6 to 0.3 +/- 0.4 ml/min and an increase of the urine/plasma osmolality ratio (143%, P less than 0.05). The decrease in urinary output and concurrent reduction of urinary sodium excretion also suggest an influence of the fall in glomerular filtration rate and renal plasma flow on renal function. IPPB only reduced total Na+ and K+ excretion. These results indicate that the mechanisms underlying the renal response to positive end-expiratory pressure breathing may be due to an increase in antidiuretic hormone plasma levels leading to a fall in urinary flow and in part to a decrease in sodium excretion.

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