Foram examinados, por meio de eletrocardiografia, 14 equinos Puro Sangue Árabe, 12 machos e duas fêmeas, desclassificados por exaustão em provas de enduro entre 60 e 160km. Foi observado predomínio de taquicardia sinusal, seguido de arritmia sinusal e complexo atrial prematuro com a frequência cardíaca variando de 48 a 78bpm e 93 a 111bpm, respectivamente. Ocorreu aumento da amplitude das ondas P, R, S e T e redução nas suas durações, bem como redução nos intervalos e segmentos, porém o complexo QRS quase não se alterou. O alongamento observado do QTc indicou fadiga miocárdica moderada em resposta ao exercício, e o supradesnível ST foi indicativo de hipovolemia. O eixo elétrico no plano frontal apresentou desvio à direita, aumento de câmara e hipertrofia secundários ao treinamento

By using electrocardiographic examination, 14 Purebred Arabian horses, 12 males and two females, disqualified due to exhaustion in endurance races from 60 and 160km were evaluated. Predominance of sinus tachycardia, followed by sinus arrhythmia and atrial premature complex, with the heart rate ranging from 48 to 78bpm, and 93 to 111bpm, respectively, were observed. There was increase in the amplitude of waves P, R, S, and T, and decrease in their durations, as well as reduction in the intervals and segments; nevertheless, the QRS complex was not almost altered. The QTc lengthening pointed to a moderate myocardial fatigue in response to exercise, and the elevation of ST was indicative of hypovolemia. The electrical axis in frontal plane presented deviation to the right, chamber increase, and hypertrophy secondary to training

Normal in vitro thyroid peroxidase (TPO) iodide oxidation activity was completely inhibited by a hydrolyzed TPO preparation (0.15 mg/ml) or hydrolyzed bovine serum albumin (BSA, 0.2 mg/ml). A pancreatic hydrolysate of casein (trypticase peptone, 0.1 mg/ml) and some amino acids (cysteine, tryptophan and methionine, 50 µM each) also inhibited the TPO iodide oxidation reaction completely, whereas casamino acids (0.1 mg/ml), and tyrosine, phenylalanine and histidine (50 µM each) inhibited the TPO reaction by 54% or less. A pancreatic digest of gelatin (0.1 mg/ml) or any other amino acid (50 µM) tested did not significantly decrease TPO activity. The amino acids that impair iodide oxidation also inhibit the TPO albumin iodination activity. The inhibitory amino acids contain side chains with either sulfur atoms (cysteine and methionine) or aromatic rings (tyrosine, tryptophan, histidine and phenylalanine). Among the amino acids tested, only cysteine affected the TPO guaiacol oxidation reaction, producing a transient inhibition at 25 or 50 µM. The iodide oxidation inhibitory activity of cysteine, methionine and tryptophan was reversed by increasing iodide concentrations from 12 to 18 mM, while no such effect was observed when the cofactor (H2O2) concentration was increased. The inhibitory substances might interfere with the enzyme activity by competing with its normal substrates for their binding sites, binding to the free substrates or reducing their oxidized form.

Os teores de 18O em águas de chuva e amostras de água de rio foram utilizados como traçadores num modelo isotópico de separação de hidrógrafas do rio Amazonas durante o período 1973-1974, com o intuito de se estimar as contribuições do escoamento superficial rápido e escoamento de base para o escoamento total da bacia de drenagem. As contribuições médias desses reservatórios foram de 30,3 e 69,7% respectivamente. Durante o período de pico de cheia, o fluxo de base contribuiu com cerca de 57% do volume total de água escoada. Os resultados do modelo de separação isotópico foram comparados com o método estatístico de filtros auto-recursivos, mostrando comportamentos similares.

The 18O content of rain and river waters was used as an isotopic tracer in order to carry out the hydrograph separation of the Amazon river, during the 1973-1974 hydrological years, and to estimate the contributions of the surface runoff (event water) and baseflow (pre-event water) components to the total river flow. The average surface runoff and baseflow contributions were 30.3 and 69.7% respectively. At peak discharge, the mean contribution of the baseflow was about 57%. The results of the isotopic separation model were compared with the filter-separation autoregressive method, showing similar behavior and magnitude.