Showing papers on "Iodine published in 1988"
TL;DR: It is indicated that a small increase in dietary iodine can induce subtle changes (all values remaining within the normal range) in pituitary-thyroid function, probably by inhibiting thyroid hormone release.
Abstract: Dietary iodine intake in the United States is greater than that considered necessary for the maintenance of normal thyroid function. The administration of pharmacologic quantities of iodine (10 to 1,000 mg daily) to euthyroid subjects results in small decreases in the serum T4 and T3 concentrations and a compensatory increase in the basal and TRH-stimulated serum TSH concentrations. Studies were carried out to determine whether a far smaller increase in iodine intake would also affect thyroid function. Normal volunteers received 1,500, 500, or 250 micrograms supplemental iodine daily for 14 days. Following the administration of 1500 micrograms iodine daily, there were small but significant decreases in the serum T4 and T3 concentrations and a small compensatory increase in the serum TSH concentration and the serum TSH response to TRH. In contrast, no changes in pituitary-thyroid function occurred during the administration of 500 or 250 micrograms iodine daily. These findings indicate that a small increase in dietary iodine can induce subtle changes (all values remaining within the normal range) in pituitary-thyroid function, probably by inhibiting thyroid hormone release. The smaller iodine supplements of 500 and 250 micrograms daily, quantities that may easily be achieved under normal conditions, did not, however, affect thyroid function.
111 citations
TL;DR: In this paper, a seasonality in the iodate/total iodide ratio in ocean waters was found to be the result of water masses becoming isolated by hydrographic effects for a sufficient time for iodate reduction to significantly change the ratio.
101 citations
TL;DR: The thyrotropic activity of purified and commercial hCG is tested and its action with that of bovine TSH (bTSH) in cultured rat FRTL-5 cells in regard to stimulation of iodide uptake, activation of adenylate cyclase, and synthesis of DNA.
Abstract: hCG stimulates thyroid function, but it has been suggested that it is impurities in commercial hCG preparations or a variant of hCG that are responsible for the thyrotropic activity. In this study, we tested the thyrotropic activity of purified and commercial hCG and compared its action with that of bovine TSH (bTSH) in cultured rat FRTL-5 cells in regard to stimulation of iodide uptake, activation of adenylate cyclase, and synthesis of DNA. Iodide uptake was measured after incubation of the cells for 48–72 h with the test hormones, followed by a 40-min incubation with 0.1 μCi Na125I and 10 μmol/L carrier Nal; the 125I in the washed cells was counted. Adenylate cyclase was measured after incubation of the cells with the test stimulators for 3 h in hypotonic medium by RIA of cAMP in the medium. DNA synthesis was measured after incubation of the cells with the test substances for 24 h, followed by addition of [3H]thymidine for 3 h and then measuring the incorporation of [3H]thymidine into the cells. Both pu...
96 citations
TL;DR: A simplified, low iodine diet was developed for outpatient use prior to I-131 scanning and therapy in thyroid cancer and this level of iodine intake may increase radioiodine uptake in thyroid carcinomas.
Abstract: A simplified, low iodine diet was developed for outpatient use prior to I-131 scanning and therapy in thyroid cancer. Iodine intake of five subjects on the diet was approximately 50 micrograms a day and this level was maintained for four weeks. The diet required only minimal instruction to be followed reliably. This level of iodine intake may increase radioiodine uptake in thyroid carcinomas.
83 citations
TL;DR: The results strongly suggest that TGF-beta inhibits TSH-stimulated iodine metabolism, at least in part, by affecting events subsequent to cAMP production.
Abstract: The effect of transforming growth factor (TGF)-β on DNA synthesis and iodine metabolism was studied in cultured porcine thyroid cells. TGF-β dose-dependently inhibited DNA synthesis stimulated by both insulin-like growth factor I and epidermal growth factor but did not affect the number or affinity of receptors for the two growth factors, suggesting that TGF-β inhibits postreceptor events responsible for initiation of DNA synthesis. TGF-β was a potent inhibitor of iodine metabolism. When porcine thyroid cells were cultured with TSH for 3 days in the presence of TGF-β, TSH-induced iodide uptake and organification were reduced at rates that were dependent on the TGF-0 concentrations. The inhibition was detectable at TGF-β concentrations as low as 50 pg/ml, and complete suppression was seen at 1 ng/ml. Only 6 h of exposure to TGF-β resulted in a significant inhibition of TSH-induced iodine metabolism. Treatment of thyroid cells with TGF-β for 3 days did not reduce cAMP production stimulated by TSH. Moreover,...
77 citations
TL;DR: It is found that iodide supplementation within the range of normal daily intake in the USA has a significant inhibitory effect on thyroid hormone secretion in normal men.
Abstract: Previous studies have demonstrated that short-term oral iodide administration, in doses ranging from 1500 micrograms to 250 mg/day, has an inhibitory effect on thyroid hormone secretion in normal men. As iodide intake in the USA may be as high as 800 micrograms/d, we investigated the effects of very low dose iodide supplementation on thyroid function. Thirty normal men aged 22-40 years were randomly assigned to receive 500, 1500, and 4500 micrograms iodide/day for 2 weeks. Blood was obtained on days 1 and 15 for measurement of serum T4, T3, T3-charcoal uptake, TSH, protein-bound iodide (PBI) and total iodide, and 24 h urine samples were collected on these days for measurement of urinary iodide excretion. TRH tests were performed before and at the end of the period of iodide administration. Serum inorganic iodide was calculated by subtracting the PBI from the serum total iodide. We found significant dose-related increases in serum total and inorganic iodide concentrations, as well as urinary iodide excretion. The mean serum T4 concentration and free T4 index values decreased significantly at the 1500 micrograms/day and 4500 micrograms/day doses. No changes in T3-charcoal uptake or serum T3 concentration occurred at any dose. Administration of 500 micrograms iodide/day resulted in a significant increase (P less than 0.005) in the serum TSH response to TRH, and the two larger iodide doses resulted in increases in both basal and TRH-stimulated serum TSH concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
66 citations
58 citations
TL;DR: In this article, the charge and discharge reactions of lithium iodide in (THF) solution on platinum are investigated with the cyclic voltammetric and rotating disk electrode techniques.
Abstract: Recently, lithium iodide has been suggested as an additive for secondary lithium batteries to prevent the oxidation of organic electrolytes during charging operations. In this study, the charge and discharge reactions of lithium iodide in (THF) solution on platinum are investigated with the cyclic voltammetric and rotating disk electrode techniques. At the anodic potentials, lithium iodide is found to undergo a two‐step process of oxidation of iodide ion to tri‐iodide ion and further oxidation of tri‐iodide ion to iodine. The diffusion coefficients of iodide and tri‐iodide ions in the electrolyte and the kinetic parameters of the redox reactions on platinum are evaluated from the rotating disk data. It is found that iodine initiates the polymerization of THF in the presence of lithium hexafluoroarsenate. To provide overcharge protection of the lithium batteries using electrolytes, large excess of lithium iodide must be present in the cell to form stable lithium tri‐iodide with the iodine generated during the charging of lithium batteries.
55 citations
TL;DR: There is no evidence for the development of thyroid dysfunction during a 6-month course of therapy with two iodine-containing mouth rinses with evidence of significant iodine absorption from daily use of both Perimed and the PVPI-water mixture.
Abstract: A prospective study was conducted to investigate the effect of long term therapy with two iodine-containing mouth rinses on thyroid function. Two groups of subjects were treated daily for 6 months with either a 5% polyvinylpyrrolidone (PVPI)-1.5% H2O2 mixture (Perimed) or a 5% PVPI-water mixture. Thyroid function studies, serum iodine concentrations, and urinary iodine excretion were measured before treatment, at 6-week intervals during the 6-month treatment period, and 3 weeks after the last treatment. There was evidence of significant iodine absorption (elevated serum total iodine and inorganic iodide concentrations and urinary iodine excretion) from daily use of both Perimed and the PVPI-water mixture. Serum T3 and T4 concentrations and the free T4 index did not change. There was a small significant rise in serum TSH concentrations during mouth rinse therapy, but all values remained within the normal range. This small increase in serum TSH is a normal adaptive response to the antithyroid effect of increased iodine intake and accounts for the maintenance of normal serum T4 and T3 concentrations. While daily use of these iodine-containing mouth rinses does result in significant iodine absorption, there is no evidence for the development of thyroid dysfunction during a 6-month course of therapy.
55 citations
TL;DR: Methods with minimal sample preparation are described for determination of iodide or bromide in serum, milk, salt and water.
TL;DR: Data demonstrate a specific inhibitory effect of organic iodine on thyroid epithelial cell growth and indicate that the inhibitory effects of NaI are mediated by some iodine-containing organic compound.
Abstract: FRTL-5 thyroid epithelial cells in culture were used to study the possible inhibitory effects of iodine on thyroid growth. Nal exerted a dose-dependent, thyroid epithelial cellspecific inhibitory effect on [methyl-3H]thymidine incorporation into DNA, reduced the DNA content in the cell layer, and limited the increase in cell number mediated by TSH. The inhibitory effects of sodium iodide applied to growth stimulated by TSH-, cAMP-, and non-cAMP-dependent mechanisms and were prevented by l-methylimidazole-2-thiol (methimazole) and 2-ethylthioisonicotinamide (ethionamide). The latter findings indicate that the inhibitory effects of Nal are mediated by some iodinecontaining organic compound. The inhibitory effects of organic iodine on growth subsided 24–48 h after removal of excess Nal from the culture medium. In contrast, Nal had no effect on normal rat kidney fibroblast or thyroid fibroblast [methyl-3H] thymidine incorporation stimulated by epidermal growth factor or serum. These data demonstrate a specifi...
TL;DR: In this paper, the in vitro characteristics of iodide and cAMP metabolism have been compared in tissues from autonomously functioning thyroid nodules and their quiescent counterpart to test the hypothesis that autonomy may result from constitutive activation of the tissue's TSH, cAMP, and protein phosphorylation regulatory axis.
Abstract: The in vitro characteristics of iodide and cAMP metabolism have been compared in tissues from autonomously functioning thyroid nodules and their quiescent counterpart to test the hypothesis that autonomy may result from constitutive activation of the tissue's TSH, cAMP, and protein phosphorylation regulatory axis, as in vivo nodular tissue took up more iodide. This effect was entirely due to increased transport capacity, the affinity of iodide transport, and the fractional binding of iodide to protein remaining unchanged. However, at high concentrations total iodide binding to protein was similar in quiescent and nodular tissue. In both tissues, this metabolic step was enhanced by phorbol esters and the ionophore A23187. As evaluated by autoradiography of two-dimensional gel protein electrophoregrams, no differences in the patterns of protein synthesis or phosphorylation between quiescent and nodular tissue were found. Basal cAMP levels were similar in quiescent and nodular tissue. The cAMP response to TSH was lower in nodular tissue, with no change in sensitivity or kinetics; both tissues responded to forskolin. No systematic suppression of iodide inhibition or abnormal responses to other hormones or neurotransmitters were found. Three proteins (24K-1, 24K-2, and 26K) were phosphorylated only in the presence of TSH or forskolin in both quiescent and nodular tissue. One protein substrate (20K) was phosphorylated in the presence of TSH in the quiescent, but not in the nodular, tissue. In conclusion, 1) slices from autonomous thyroid nodules reproduce the in vivo characteristics of the lesion and are, therefore, a suitable in vitro experimental model for biochemical studies; 2) taken together with data from transplantation experiments, the reproduction in vitro or its in vivo characteristics suggest an inherent defect in the nodule; 3) the homogeneity of biochemical findings within each nodule is compatible with the clonality of the lesion; 4) the autonomous nodule is a minimal deviation tumor; and 5) the characteristics of the TSH, cAMP, protein phosphorylation cascade are qualitatively normal, and autonomy does not result from constitutive activation of this system; and 6) a 20K protein, not phosphorylated in response to TSH in the nodule, could represent an absent negative controlling element.
TL;DR: In the Randers area of Denmark, urinary iodine excretion (which reflects iodine intake) was found to be much lower than recommended intake levels, both in women in late pregnancy and in non-pregnant controls.
Abstract: In the Randers area of Denmark urinary iodine excretion (which reflects iodine intake) was found to be much lower than recommended intake levels, both in women in late pregnancy [52(23–118) pg iodine/g creatinine, median, range, n = 20] and in non-pregnant controls [42(23–711, n = 20]. Serum thyroglobulin which is high in iodine deficiency was 32.5 pgA (median) (range 10.5–78.0) in the control women and considerably higher in the pregnant women [67.0 pgll (9.0–385)]. This increase was probably due to the extra iodine requirement of pregnancy which was not satisfied with an adequate increase in iodine intake. The results may suggest that pregnant women in this area should receive iodine supplementation and that a general program of iodine supplementation should be considered.
TL;DR: Investigation of the effect of excess iodide alone, following iodide depletion or in conjunction with a mild thyroid insult in Buffalo strain rats provides further support for a role for dietary iodine in modulating experimental autoimmune thyroiditis with implications for human thyroid autoimmunity.
Abstract: We have investigated the effect of excess iodide alone, following iodide depletion or in conjunction with a mild thyroid insult (trypan blue) in Buffalo strain rats, which are genetically susceptible to experimental autoimmune thyroiditis. In all three cases a high iodine diet led to enhanced thyroglobulin antibody production, usually accompanied by worsening of the severity of thyroiditis. Moreover, the administration of a normal iodine diet after iodide depletion resulted in thyroglobulin antibody formation. These results provide further support for a role for dietary iodine in modulating experimental autoimmune thyroiditis with implications for human thyroid autoimmunity.
TL;DR: A comprehensive multicompartmental kinetic model was developed to account for the distribution and metabolism of simultaneously injected radioactive iodide, T3 (T3*), and T4 (T4*) in six normal and seven spontaneously hyperthyroid cats, and all of the exchange parameters for both T4 and T3 were significantly slowed inhyperthyroidism.
Abstract: A comprehensive multicompartmental kinetic model was developed to account for the distribution and metabolism of simultaneously injected radioactive iodide (iodide*), T3 (T3*), and T4 (T4*) in six normal and seven spontaneously hyperthyroid cats. Data from plasma samples (analyzed by HPLC), urine, feces, and thyroid accumulation were incorporated into the model. The submodels for iodide*, T3*, and T4* all included both a fast and a slow exchange compartment connecting with the plasma compartment. The best-fit iodide* model also included a delay compartment, presumed to be pooling of gastrosalivary secretions. This delay was 62% longer in the hyperthyroid cats than in the euthyroid cats. Unexpectedly, all of the exchange parameters for both T4 and T3 were significantly slowed in hyperthyroidism, possibly because the hyperthyroid cats were older. None of the plasma equivalent volumes of the exchange compartments of iodide*, T3*, or T4* was significantly different in the hyperthyroid cats, although the plasm...
TL;DR: Chronic L-thyroxine administration for 2 or 3 months suppressed serum TSH concentrations and decreased both the incidence of spontaneous lymphocytic thyroiditis (LT) and the serum levels of anti-thyroglobulin (anti-Tg) antibodies in the diabetes prone BB/Wor rat.
Abstract: Chronic L-thyroxine administration (6ug/100g BW, ip, daily) for 2 or 3 months suppressed serum TSH concentrations and decreased both the incidence of spontaneous lymphocytic thyroiditis (LT) and the serum levels of anti-thyroglobulin (anti-Tg) antibodies in the diabetes prone BB/Wor rat. This suggests that TSH may play a role in the occurrence of LT in this rat model. In contrast to these observations, L-thyroxine administration did not affect the markedly increased incidence of LT or the elevated serum anti-Tg antibodies in iodine supplemented BB/Wor rats, suggesting that TSH stimulation is not necessary for the development of iodine induced LT in this rat model. Other factors, such as the increased antigenicity of highly iodinated Tg, may be more important.
TL;DR: In this paper, a catalyzed coupling of 4 and 3,3-dimethylbutynylstannane results in the formation of Terbinafine (1a ).
TL;DR: It is demonstrated, for the first time, that iodinated derivatives of arachidonic acid inhibit thyroid function and mimic the effect of iodide on thyroid autoregulation.
TL;DR: It is concluded that oral iodized oil is an effective alternative to injected oil and would be feasible for iodine supplementation in remote areas with untrained people.
Abstract: A community-based controlled trial of iodine supplementation comparing oral or intramuscular iodized oil with oral potassium iodide has been carried out in 23 severely iodine-deficient villages in Eastern Zaire. The overall goitre prevalence in the population (n = 5999) was 61% and mean urinary iodine excretion in sample of 57 women 10.9 (SD 6.8) micrograms/g creatinine. All adults in three groups of four villages were given single doses of potassium iodide of 0.5 g, 1.0 g, and 2.0 g respectively. A fourth group was given oral iodized oil (2 ml) and a fifth placebo-treated. A further three villages were given intramuscular iodized oil (2 ml). The effectiveness of supplementation was assessed by measurements of bloodspot thyroxine (T4) concentration in women of reproductive age in the villages. The effects of iodide were small and inconsistent. Eight months after supplementation with oral iodized oil the distribution of T4 concentrations was similar to that seen with intramuscular oil. We conclude that oral iodized oil is an effective alternative to injected oil and would be feasible for iodine supplementation in remote areas with untrained people.
TL;DR: The follicular heterogeneity of thyroid response to progressive chronic TSH stimulation induced by LID is demonstrated, showing a progressive decrease of the luminal iodine concentration which on day 80 was 10‐fold lower than that of control value.
TL;DR: In this article, the anodic oxidation of iodide on platinum in concentrated iodide + iodide solutions has been investigated using a rotating disc electrode, and the dissolution-diffusion control mechanism of the iodine film is confirmed.
TL;DR: The present results suggest that the response of the freshly isolated tissue to phorbol esters, NE and carbachol differs from that of cells in culture with respect to an important metabolic function of the thyroid gland.
Abstract: The effect of TSH, phorbol ester, norepinephrine (NE), and carbachol, agents known to influence thyroid metabolism, was compared on iodide organification in dog thyroid slices, freshly isolated follicles, and cultured cells. TSH stimulated iodide organification in all three types of preparations, and this effect was mimicked by (Bu)2cAMP. In contrast, the phorbol ester, tetradecanoyl phorbol acetate (TPA) stimulated iodide organification in slices and follicles but inhibited it in cells. The dose and time required for these divergent effects were similar. Other stimulators of protein kinase C such as aplysiatoxin and teleocidin mimicked the effects of TPA, and these effects were partially reversed by H-7, an inhibitor of protein kinase C. Pretreatment of cells with TPA for 4 h did not affect TSH-stimulated cAMP production, but TPA inhibited iodide organification in cells even in the presence of TSH or (Bu)2cAMP. Similarly NE and carbachol stimulated iodide organification in follicles but inhibited it in c...
TL;DR: In this paper, the authors used quadrupole mass spectrometers to study the chemical form and rate of release of volatile fission products (e.g., Xe, Kr, Cs, Te, and I) effusing from irradiated LWR fuel samples.
TL;DR: Two simple methods, isotope exchange method and anion exchanger column method, are developed for the determination of chemical forms of radioiodine (iodide and iodate) in water samples.
Abstract: Two simple methods, (1) isotope exchange method and (2) anion exchanger column method, are developed for the determination of chemical forms of radioiodine (iodide and iodate) in water samples. Using these methods, transformations of chemical forms of iodine in various water samples were studied. It was observed that iodate in rain water (unfiltered) and milk tended to change iodide form, whereas iodide was converted to iodate form in seawater and tap water. After the Chernobyl accident both chemical forms of131I (iodide and iodate) were found in rain water samples collected in Japan.
TL;DR: It is concluded that an l/Cr ratio of 151–200, corresponding to an iodine intake of about 200 µg/day, is associated with the lowest TSH stimulation of the thyroid gland in man and probably represents the optimal conditions for its function.
Abstract: The urinary iodine excretion, expressed as the iodine/creatinine (l/Cr) ratio, was correlated with the serum T4 and TSH levels in persons with a relatively constant iodine intake for at least 6 months. It was found that the group with an I/Cr ratio of 151–200 µg/g had on average the lowest serum TSH and the highest serum T4 level. The differences in serum TSH from the other groups were statistically significant, whereas the differences in serum T4 were not. It is concluded that an l/Cr ratio of 151–200, corresponding to an iodine intake of about 200 µg/day, is associated with the lowest TSH stimulation of the thyroid gland in man and probably represents the optimal conditions for its function.
Patent•
22 Sep 1988
TL;DR: A pharmaceutical iodophor preparation having predictable microbicidal effectiveness and long duration of action comprising polyvinylpyrrolidone-iodine (PVPI), free iodine, a source of iodide ions and a sourceof iodate ions, the preparation having a ratio of available (titratable) iodine to iodide between 2:1 and 10:1, a pH between 5 and 6 and a free iod concentration between 2 and 20 ppm, wherein the amount of iodate ion in the preparation is sufficient to maintain the free iodine concentration for at least 12 months
Abstract: A pharmaceutical iodophor preparation having predictable microbicidal effectiveness and long duration of action comprising polyvinylpyrrolidone-iodine (PVPI), free iodine, a source of iodide ions and a source of iodate ions, the preparation having a ratio of available (titratable) iodine to iodide between 2:1 and 10:1, a pH between 5 and 6 and a free iodine concentration between 2 and 20 ppm, wherein the amount of iodate ion in the preparation is sufficient to maintain the free iodine concentration between 2 and 20 ppm for at least 12 months at 20° C.
TL;DR: The dry digestion of the sample, carried out in a nickel crucible, and its preparation are described, and the relative standard deviation of the results obtained using the suggested schedule is not more than 2% for amounts up to 60 ng.
Abstract: An analysis schedule for the determination of total iodine in biological materials has been developed. The reaction on which the determination is based is the known catalytic action of iodide on the redox system cerium(IV)-arsenic(III). The dry digestion of the sample, carried out in a nickel crucible, and its preparation are described. The relative standard deviation of the results obtained using the suggested schedule is not more than 2% for amounts up to 60 ng. The analysis schedule was tested for the determination of iodine in various biological materials.
TL;DR: A method is described for determination of sulphoxides through their reaction with iodide in a trifluoroacetic acid/acetone medium to produce iodine, which is then titrated with thiosulphate.