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Biomedical subjects

E Roti

Publications and source records attributed to E Roti.

At least 109 records · Page 6Linked to original sources

"Short" loop feedback regulation of hypothalamic and brain thyrotropin-releasing hormone content in the rat and dwarf mouse.

In order to determine whether T4, TSH, or both affect hypothalamic TRH content, primary or secondary hypothyroidism was induced in the rat by thyroidectomy (Tx) or hypophysectomy (Hx), respectively. Two weeks later, rats were treated with T4, TSH, or both for 14--16 days. Tx or Hx significantly decreased hypothalamic TRH content, and T4 treatment restored hypothalamic TRH to normal in the Tx but not in the Hx rats. When TSH was administered simultaneously with T4 to Hx rats, hypothalamic TRH content was restored to normal. Whole brain TRH content was not affected by Tx, Hx, or by the various treatment regimens. Similar experiments were performed in Snell dwarf (dw/dw) mice. Hypothalamic TRH content was significantly decreased when compared to normal litter mates (dw/+). As in Hx rats, T4 administration to dw/dw mice for 16 days did not restore hypothalamic TRH content to normal. Brain TRH content was similar in both groups and was not altered by T4 treatment. It is concluded that T4 affects hypothalamic TRH content, but that TSH is required for this T4 effect. Whole brain TRH, on the other hand, is unaffected by any of these alterations in thyroid-pituitary function.

Animals↗

Effect of iodine administration on thyroid function in diabetic patients.

Iodide-induced hypothyroidism has been observed in subjects treated with compounds with mild antithyroid activity. The hypoglycemic agent tolbutamide belongs to the aminoheterocyclic group, a class of compounds with antithyroid effect. Thus it was thought interesting to study the effect of large doses of iodide on thyroid function in diabetics chronically treated with tolbutamide. Basal thyroid function as assessed by clinical examination and iodothyronine and TSH concentrations was normal in all patients. Furthermore, in diabetics treated with tolbutamide, hormone concentrations were not different from those of patients treated with insulin or diet. Serum T4, T3 and TSH did not show any significant variation throughout the investigation period. Our results suggest that thyroid function is not affected by chronic treatment with tolbutamide even when large doses of iodide are administered.

Aged↗

Serum concentrations of myoglobin, creatine kinase, lactate dehydrogenase and cardiac isoenzymes in euthyroid, hypothyroid and hyperthyroid subjects.

Serum concentrations of myoglobin, creatine kinase and lactate dehydrogenase were measured in 33 euthyroid, 21 hyperthyroid and 15 hypothyroid subjects. The results showed that myoglobin, creatine kinase and lactate dehydrogenase were increased and decreased in the hypo- and hyperthyroid states, respectively. In addition, the concentrations of myoglobin, creatine kinase and lactate dehydrogenase values were inversely related to both the thyroxine and triiodothyronine concentrations. To study the origin of the increased muscle protein values observed in hypothyroidism, the cardiac isoenzyme fractions were measured; the results obtained support the view that the muscle enzymes are mainly derived from skeletal muscles.

Adult↗

Iodothyronine and thyrotropin concentrations after iodoamide administration for angiographic studies.

In order to study the effect of iodoamide (a contrast medium widely used for urographic and arteriographic studies) on thyroid function, seventeen subjects were studied before and after arteriographic examinations employing this contrast compound. Serum concentrations of T4, T3, rT3 and TSH were not modified during the observation period by the administration of iodoamide. This finding is in contrast with the observation that iopanoic acid and ipodate, used for cholecystographic examinations, can reduce the serum concentrations of T4 and T3 with a concomitant increase in rT3. Therefore, iodoamide is not useful in the treatment of hyperthyroidism.

Adult↗

Selenium administration does not cause thyroid insufficiency in subjects with mild iodine deficiency and sufficient selenium intake.

Selenium is a trace element essential for the activity of type I 5'-deiodinase which converts thyroxine (T4) to 3,5,3'-triiodothyronine (T3). In iodine deficient hypothyroid children at low selenium dietary intake the supplementation of selenium induced a significant decrement of serum FT4 and T4 concentrations and an increase of serum TSH concentrations. Since in western countries selenium tablets begin to be largely consumed as a diet integrator, we have administered 100 micrograms/day of selenium as selenium methionine to 8 euthyroid female subjects with a positive iodine-perchlorate discharge test who had a previous episode of subacute or postpartum thyroiditis. We have studied subjects with positive iodine-perchlorate discharge test since the test indicates the existence of a subtle defect of thyroid hormone synthesis and therefore these subjects are prone to develop thyroid dysfunction. In contrast to previous findings in hypothyroid children at low iodine and selenium dietary intake, the supplementation of selenium did not decompensate thyroid hormone synthesis of euthyroid subjects with reduced thyroid iodine organification. The lack of any effect of selenium on thyroid hormone synthesis even in subjects with subtle thyroid hormone synthesis defect may be due to the fact that these subjects had a sufficient selenium dietary intake before selenium supplementation and an only marginally reduced dietary iodine intake.

Adult↗

3,3',5'-Triiodothyronine concentrations in amniotic fluid at different stages of pregnancy.

Since it is feasible to detect reverse T3 (rT3) in amniotic fluid, we investigated the possibility as to whether measurements of amniotic rT3 could be useful in diagnosing fetal hypothyroidism during pregnancy. In 55 amniotic fluid samples, obtained at different stages of pregnancy, we have documented increasing concentrations of this hormone. The results obtained are conflicting with previous reports. The reason for this discrepancy is not clear, however methodological differences in rT3 determination should be taken in account. The large scatter of rT3 values in amniotic fluid suggests that the diagnosis of neonatal hypothyroidism based on measurement of rT3 may require caution.

Amniotic Fluid↗

Effects of somatostatin in a case of severe hypoglycemia due to nesidioblastosis.

The Authors have studied the effects of somatostatin (SRIF) treatment in an infant affected by hypoglycemia due to nesidioblastosis. During iv infusion with SRIF we observed a marked increase of blood glucose levels; concomitantly insulin secretion was almost completely suppressed. In contrast, during treatment with protamine zinc-somatostatin (PZ-SRIF), a long acting SRIF preparation, the blood glucose levels did not rise and insulin concentrations were inappropriately elevated. Therefore in this case the long term treatment of hypoglycemia due to nesidioblastosis with PZ-somatostatin was unfeasible.

Adenoma, Islet Cell↗

The value of serum thyroglobulin measurement as a marker of cancer recurrence in the follow-up of patients previously treated for differentiated thyroid tumor.

In order to verify the value of serum thyrogolbulin (hTg) determination to detect cancer recurrence, 104 patients previously treated with surgical and 131I total thyroid ablation of differentiated thyroid cancer were studied. Comparison of serum hTg results and 131I total body scans (131I TBS) was attempted. In 87 patients with negative 131 I TBS, serum hTg was undetectable in 80% of the patients whereas in 20% detectable amounts of hTg were measured. In 57 patients with positive 131I TBS, serum hTg was measurable in 72% of the patients whereas in 20% was undetectable. These contrasting results of serum hTg measurement and 131I TBS suggest to us the usefulness to use both tests in the detection of thyroid cancer recurrence.

Female↗

Clinical evaluation of a hemagglutination method for microsomal and thyroglobulin antibodies in autoimmune thyroid disease.

A simple and reproducible hemagglutination technique for detecting microsomal and thyroglobulin antibodies has been evaluated in normal subjects and in patients with thyroid disease. Microsomal antibodies were detected in 89 percent of all patients with autoimmune thyroid disease and in 97 percent of patients with biopsy proven Hashimoto's thyroiditis. In contrast, thyroglobulin antibodies were present in only 55 percent of patients with biopsy proven Hashimoto's thyroiditis and in 44 percent of all patients with suspected autoimmune thyroid disease. It is suggested, therefore, that measurement of microsomal antibodies by a simple hemagglutination techniques be carried out in all patients with suspected thyroid disorders.

Antibodies↗