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Biomedical subjects

R Téllez

Publications and source records attributed to R Téllez.

At least 19 recordsLinked to original sources
PubMed2000

Does perchlorate in drinking water affect thyroid function in newborns or school-age children?

Perchlorate is known to suppress thyroid function by inhibiting uptake of iodide by the human thyroid at doses of 200 mg/day or greater. A study was conducted to investigate the potential effects of perchlorate in drinking water on thyroid function in newborns and school-age children. A total of 162 school-age children and 9784 newborns were studied in three proximate cities in northern Chile that have different concentrations of perchlorate in drinking water: Taltal (100 to 120 micrograms/L), Chañaral (5 to 7 micrograms/L), and Antofagasta (non-detectable: < 4 micrograms/L). Among schoolchildren, no difference was found in thyroid-stimulating hormone levels or goiter prevalence among lifelong residents of Taltal or Chañaral compared with those of Antofagasta, after adjusting for age, sex, and urinary iodine. No presumptive cases of congenital hypothyroidism were detected in Taltal or Chañaral; seven cases were detected in Antofagasta. Neonatal thyroid-stimulating hormone levels were significantly lower in Taltal compared with Antofagasta; this is opposite to the known pharmacological effect of perchlorate, and the magnitude of difference did not seem to be clinically significant. These findings do not support the hypothesis that perchlorate in drinking water at concentrations as high as 100 to 120 micrograms/L suppresses thyroid function in newborns or school-age children.

Age Distribution↗
PubMed1998

[Thyroid function in a population with an extra iodine intake].

BACKGROUND: After 20 years of iodine salt fortification, the prevalence of goiter has decreased significantly in the rural area of Pirque, central Chile. In this location, equipment has been installed that efficiently and economically adds 0.5 mg of elemental iodine per liter of water to render it potable. AIM: To study thyroid function and urinary iodine excretion in school age children of this zone, after two years of extra iodine intake. MATERIAL AND METHODS: One hundred thirty four children aged 6 to 12 years old were examined. In 56 randomly chosen children a morning urine sample was obtained to measure iodine excretion. In 45 children without goiter, a blood sample was drawn to measure TSH and thyroxin. RESULTS: In nine children (7%) a diffuse goiter was found. Median urinary iodine excretion was 158 micrograms/dl. Thyroxin and TSH levels were within normal limits (8.4 +/- 1.1 micrograms/dl and 2.2 +/- 1.5 microU/ml respectively). During the period of iodine water supplementation there were 47 births in the zone. All newborns had normal TSH values and none had goiter. CONCLUSIONS: When present results are compared with the period before water iodination (when the prevalence of goiter was 9.6% and mean urinary iodine excretion was 57.6 micrograms/dl), it can be concluded that extra iodine intake in this rural population has not caused additional thyroid problems.

Child↗
PubMed1996

[Prevalence of goiter in school-age children in the Pirque Zone. Effects of salt iodination].

BACKGROUND: Twenty years ago, Pirque was a zone with a goiter prevalence of 39%. AIM: To assess the effects of salt iodination on the prevalence of goiter in school-age children of this zone. SUBJECTS AND METHODS: School age children from four public schools in Pirque were examined, following WHO criteria for the diagnosis of goiter. Urinary iodine excretion was also measured. RESULTS: Five hundred ninety one males and 298 females aged 12.1 +/- 2.5 years were examined. Fifty seven children (9.6%) bad goiter. In 53 the goiter was grade I and in 4, grade II. No sex differences were observed. Minimal and median urinary iodine excretion values were 12.6 and 57.6 micrograms/dl respectively. CONCLUSIONS: Goiter prevalence dropped from 39 to 10%. The fact that iodine intake is over minimal recommendations, underscores the effectiveness of salt iodination.

Adolescent↗
PubMed1996

[Diffuse fatty infiltration of the thyroid gland associated to amyloidosis in a patient with chronic renal failure].

We report a 26 years old male with secondary amyloidosis and chronic renal failure who consulted due to a rapidly growing goiter associated with coarseness and dysphagia. Serum levels of thyroid hormones and TSH were normal and a neck CT scan showed a big mass in the anterior and lateral regions, that compressed neighboring structures. The patient was subjected to a total thyroidectomy and the pathological study revealed a diffuse fatty and amyloid infiltration of the thyroid gland. There was no evidence of malignancy.

Adipose Tissue↗
PubMed1995

[Clinical evaluation of body hair in healthy women].

AIM: to study the amount and distribution of terminal body hair in non-hirsute women consulting in a public outpatient clinic. PATIENTS AND METHODS: two hundred thirty six premenopausal women consulting in a birth control clinic or consulting for acute non-endocrinological diseases were studied. Body hair was assessed with a semi-quantitative clinical method described by Ferriman and Gallwey. RESULTS: Ninety-five percent of women had a score equal or less than 5. No correlations were found between the score and body mass index or age. Partial scores over 1 were found specially in the lower abdomen, chest, superior lip and thighs. CONCLUSIONS: This sample of women, coming from middle and low socioeconomic levels, appears more hairless than European or North American Women. Thus, hirsutism must be suspected with scores over 5. These results cannot be extrapolated to all Chilean women, due to differences in ethnical backgrounds.

Adolescent↗
PubMed1994

[Hypothyroid myopathy. Communication of 4 cases].

We report four patients with primary hypothyroidism (3 female, aged 47, 46, 49 and 34 years old) whose principal manifestation was muscle involvement. The diagnosis was oriented by the finding of myoedema and a slow relaxation phase of tendon reflexes. In one patient, an electromyographic and histological study was performed. Thyroid substitution lead to an improvement in myopathy in all patients.

Adult↗
PubMed1993

[Major adverse reactions to propylthiouracil in 586 cases of hyperthyroidism].

Aiming to know the incidence and evolution of major adverse reactions to propylthiouracil in patients with hyperthyroidism, we performed a retrospective analysis of 586 patients treated between 1982 and 1992. All known complications associated to the use of propylthiouracil were considered major adverse reactions, when other causes were discarded. Eight patients (1.4% of the sample) had major adverse reactions: three had agranulocytosis, 3 hepatitis, 1 cholestasis and 1 vasculitis. All had a good evolution after discontinuing the drug. The patients with agranulocytosis were treated with antibiotics and the patient with cholestasis received prednisone. We conclude that major adverse reactions to propylthiouracil are infrequent, that they occur preferentially during the first months of treatment, earlier after reexposure and that there was no associated mortality.

Adolescent↗
PubMed1993

[Autoimmune thyroid pathology of pregnancy and puerperium. Prevalence in a zone of endemic goiter and its impact on the newborn].

The aim of this work was to study the prevalence of thyroid disease in pregnant and puerperal women and newborns in Pirque (Chile) and its possible relation to iodine intake or autoimmune disease. Two hundred twenty eight women with 13.4 +/- 3.4 weeks of pregnancy were examined initially and in 223, laboratory tests were performed. Goiter was found in 107 women. Although all women were euthyroid, those with goiter had higher serum levels of T3 and T4. Nineteen women had positive anti-thyroid antibodies and urinary iodine excretion was > 100 micrograms/g creatinine in 87.2%. Within 2 and 57 weeks after delivery (mean 13.5 weeks), 183 women were reexamined and in 175 laboratory tests were performed. Serum T3 continued to be higher in those with goiter. Fifteen women with positive anti-thyroid antibodies during pregnancy continued to have positive titres; of these, two had a post partum thyroiditis and one a graves disease. Two hundred three newborns were examined and no one had goiter or elevated TSH. It is concluded that there is a high frequency of goiter among pregnant and puerperal women from Pirque, that iodine intake is normal and that there is a low frequency of post partum thyroiditis.

Adolescent↗
PubMed1991

A prepubertal surge of thyrotropin precedes an increase in thyroxine and 3,5,3'-triiodothyronine in normal children.

The variations in plasma levels of TSH, T4, T3, and rT3, during the pubertal period, were studied in 647 school students from the urban area of Santiago in Chile (47% males and 53% females) with ages ranging between 7.5 and 15 yr. The subjects were grouped by age in consecutive intervals of 6 months each, and pubertal development was determined in every subject. TSH showed a significant increase, reaching a peak in the 9- to 9.5-yr interval. The same was found for T3 and T4, which reached a peak by 10 and 11 yr. The T4/T3 ratio did not show any significant variation with age. After 9.5 yr, a decrease in rT3 and increase in the T4/rT3 ratio was found. The TSH peak preceded the onset of clinical pubertal development, while the T3 and T4 peaks coincided with this onset. The variations in rT3 suggest an increase of peripheral conversion of T4 to T3. These transient events, not described until now, could be termed thyroidarche and could have a significant effect on pubertal growth and development.

Adolescent↗
PubMed1991

[Catheterization of petrous sinus and selective determination of ACTH: usefulness in the management of Cushing's syndrome in 2 cases].

Two patients with Cushing's syndrome are reported. The syndrome was the consequence of relapse after transphenoidal resection of a pituitary tumor in one and due to occult ACTH secretion in the other. Determination of ACTH after bilateral petrosal sampling in both cases and after systemic venous sampling at different sites in one, allowed localization of the source of hormone secretion which was confined to one side of the hypophysis in one case and to the thorax in the other. Hypophyseal resection in the first case and bilateral adrenal resection in the other were performed successfully. The value of this diagnostic test is analyzed.

ACTH Syndrome, Ectopic↗
PubMed1988

Proteolysis of mitochondrial-coded and nuclear-coded proteins found in yeast mitochondria.

The rate of degradation of radioactive labeled mitochondrial proteins synthesized both in vitro and in vivo by isolated yeast mitochondria and growing yeast cells respectively, has been studied. It was found that the in vitro-synthesized mitochondrial proteins are rapidly degraded by an energy-dependent proteolytic system. Under the same experimental conditions the in vivo-synthesized mitochondrial proteins are slowly degraded to a limited extent by a protease which is slightly inhibited by ATP. During this period, the mitochondria are coupled and metabolically active. It is proposed that mitochondria possess an energy-dependent proteolytic system that recognizes as substrates either "abnormal" proteins or unassembled protein subunits encoded in the mitochondrial genome. An apparently different system, which is independent of energy, seems to be responsible for the slow and limited degradation of "normal" mitochondrial proteins.

Adenosine Triphosphatases↗
PubMed1985

Effect of ethionine on the in vitro synthesis and degradation of mitochondrial translation products in yeast.

The effect of ethionine, an amino acid analog of methionine, has been studied in Saccharomyces cerevisiae in relation to cell growth, oxygen consumption, in vitro protein synthesis of mitochondrial translation products (MTPs) and the degradation of those mitoribosomally made proteins by an ATP-dependent process present within the organelle. Ethionine was found to increase the generation time of those cells already committed to cell division and to abolish the initiation of new cell cycles. Oxygen consumption of cultures grown in the presence of the analog was drastically reduced. Ethionine was also found to impair the incorporation of methionine and leucine into mitochondrial translation products, however the synthesis of proteins was not totally blocked and, apparently, mitochondria utilized ethionine as a precursor amino acid. MTPs synthesized by isolated mitochondria in the presence of ethionine were rapidly degraded inside the organelle at a faster rate compared with the normal proteins synthesized under identical conditions in the mitochondria. It is also shown that these in vitro synthesized proteins are degraded by an ATP-stimulated proteolytic system, as has been previously established.

Adenosine Triphosphate↗