Iodine

About: Iodine is a research topic. Over the lifetime, 8936 publications have been published within this topic receiving 139981 citations. The topic is also known as: I & element 53.

Combination of potassium iodide and propranolol in preparation of patients with Graves' disease for thyroid surgery.

Abstract: We assessed the efficacy of the combination of propranolol and potassium iodide in the preparation of patients with Graves' disease for thyroid surgery. Potassium iodide was given orally in a dose of 60 mg three times a day for 10 days before operation in 10 patients who were already receiving propranolol. In contrast to previous experience with either drug used singly, the combined regimen caused a significant fall in mean serum total thyroxine and triiodothyronine to levels in the euthyroid range before operation (P less than 0.001). There was also a significant fall (P less than 0.05) before operation and transient rise after operation in serum reverse triiodothyronine. These preliminary results suggest that the combination of potassium iodide and propranolol may prove to be the optimum preoperative preparation for patients with Graves' disease.

Effect of iodide concentration on thyroxine synthesis catalysed by thyroid peroxidase.

Abstract: Thyroglobulin with a low content of iodine atoms per molecule of protein was incubated with thyroid peroxidase and increasing iodine concentrations (0.01 to 4 mM). 1 When iodide was in great excess (4 mM), I2 was the only product, protein iodination being markedly or completely inhibited. At low iodide concentrations (0.2 mM and below) no I2 was formed. A clear competition between these two possible reactions catalysed by thyroid peroxidase was therefore demonstrated. 2 When iodide concentration was less than 0.5 mM, thyroid peroxidase catalysed only the iodination of thyroglobulin. Thyroid hormones began to accumulate when the iodination reaction leveled off. Different observations suggest that thyroxine was synthesised mainly by the coupling of two diiodotyrosine residues rather than by the iodination of 3,5,3′-triiodothyronine residues. 3 With very low iodide concentration, the synthesis of hormones began soon after the formation of hormonogenic residues. However the iodination reaction being faster than the coupling reaction, highly iodinated thyroglobulin could be obtained which did not contain thyroid hormones. From these results it appears that thyroid peroxidase is able to enter into at least three reactions: iodide peroxidation, tyrosine residues iodination and coupling of iodotyrosine residues to thyroid hormones. Surprisingly, this relative unspecificity of thyroid peroxidase may have some regulatory physiological significance.

Geographical distribution of drinking-water with high iodine level and association between high iodine level in drinking-water and goitre: a Chinese national investigation.

Abstract: Excessive iodine intake can cause thyroid function disorders as can be caused by iodine deficiency. There are many people residing in areas with high iodine levels in drinking-water in China. The main aim of the present study was to map the geographical distribution of drinking-water with high iodine level in China and to determine the relationship between high iodine level in drinking-water and goitre prevalence. Iodine in drinking-water was measured in 1978 towns of eleven provinces in China, with a total of 28,857 water samples. We randomly selected children of 8-10 years old, examined the presence of goitre and measured their urinary iodine in 299 towns of nine provinces. Of the 1978 towns studied, 488 had iodine levels between 150 and 300 μg/l in drinking-water, and in 246 towns, the iodine level was >300 μg/l. These towns are mainly distributed along the original Yellow River flood areas, the second largest river in China. Of the 56 751 children examined, goitre prevalence was 6.3 % in the areas with drinking-water iodine levels of 150-300 μg/l and 11.0 % in the areas with drinking-water iodine >300 μg/l. Goitre prevalence increased with water and urinary iodine levels. For children with urinary iodine >1500 μg/l, goitre prevalence was 3.69 times higher than that for those with urinary iodine levels of 100-199 μg/l. The present study suggests that drinking-water with high iodine levels is distributed in eleven provinces of China. Goitre becomes more prevalent with the increase in iodine level in drinking-water. Therefore, it becomes important to prevent goitre through stopping the provision of iodised salt and providing normal drinking-water iodine through pipelines in these areas in China.