Showing papers on "Iodine published in 1987"

The Incorporation of Dietary Iodine into Thyroglobulin Increases Its Immunogenicity

Abstract: Experiments were performed to analyze one mechanism by which elevated levels of dietary iodine may induce thyroglobulin (Tg) autoantibodies. We tested the hypothesis that highly iodinated Tg synthesized by animals fed a high iodine diet is significantly more immunogenic than Tg containing fewer iodine atoms. Cornell strain (CS) chickens, genetically susceptible to iodide-induced thyroiditis, were fed either a high or a low iodine diet. They were killed, and their thyroidal Tg was analyzed for iodine; the high iodine Tg (HI-Tg) had at least 60 and the low iodine Tg (LI-Tg) had less than 13 atoms/molecule of Tg. To determine if the degree of Tg iodination affected its immunogenicity, these Tg preparations were administered iv to normal chickens without adjuvants. Their sera were tested for antibodies by direct binding radioassays and RIAs. HI-Tg stimulated the synthesis of antibodies that reacted well with HI-Tg and the thyroid hormones T3 and T4, but only weakly with LI-Tg. The birds immunized with LI-Tg produced very little antibody to LI-Tg, T3, or T4, but a modest amount to HI-Tg. In other experiments, Tg autoantibodies found in chickens maintained on a high iodine diet similarly demonstrated enhanced binding to HI-Tg. The present studies show that HI-Tg is more immunogenic than LI-Tg and supports the hypothesis that a high iodine diet induces Tg autoantibodies by increasing the immunogenicity of the Tg molecule. In marked contrast with iodide-induced Tg antibodies, the Tg antibodies accompanying the severe and early-onset thyroiditis of obese strain chickens are to a large degree independent of dietary iodine intake.

Amiodarone: a common source of iodine-induced thyrotoxicosis.

Abstract: Amiodarone, a iodine-rich drug widely used in the treatment of tachyarrythmias, represents one of the most common sources of iodine-induced thyrotoxicosis. The data concerning 58 patients with amiodar

Electrochemistry of Iodide in Propylene Carbonate I . Cyclic Voltammetry Monitored by Optical Spectroscopy

Abstract: The electrochemistry of iodide in propylene carbonate (PC) was investigated using cyclic voltammetry. In an anodic sweep, iodide is oxidized sequentially to triiodide and then to iodine according to 3I/sup -/ ..-->.. I/sub 3//sup -/ + 2e/sup -/ (I) 2I/sub 3//sup -/ ..-->.. 3I/sub 2/ + 2e/sup -/ (II). This mechanism was confirmed using UV-visible spectroscopy in conjunction with cyclic voltammetry experiments at a thin gold mesh electrode. Potential step experiments were used to measure a diffusion coefficient of 4 X 10/sup -6/ cm/sup 2//s for iodide in a KAsF/sub 6/ PC electrolyte.

Hypertrophy and hyperplasia during goitre growth and involution in rats--separate bioeffects of TSH and iodine.

Abstract: Goitre growth was investigated in rats receiving a low iodine diet (less than 0.1 microgram iodine/g) and either 1 g/l KClO4 or 1 g/l propylthiouracil (PTU), or a combination of KClO4 or PTU with 50.82 nmol/1 T3 in tap water for 3 weeks. To investigate goitre involution, rats with iodine-deficient goitres were treated for 3 weeks either with T3 (0.5 microgram T3/day = 0.768 nmol/day), iodide (0.5 or 2.7 micrograms KI/day) or a combination of T3 with both iodide doses. Histology together with total DNA distinguished between hypertrophy and hyperplasia of the gland. During goitre growth there was highly significant correlation between goitre weight and TSH serum level (r = 0.93, P less than 0.001). Thyroid total DNA, however, was only weakly correlated to TSH but was inversely related to the degree of iodine deficiency. During goitre regression, TSH levels were normalized, histological signs of hypertrophy had disappeared, and thyroid weight was nearly normalized in all therapy groups. Total DNA, however, was normalized only with 2.7 micrograms KI/day (95 +/- 18 micrograms DNA/gland), and still elevated in all other groups. The highest DNA levels were found under T3 therapy (143 +/- 21 micrograms DNA/gland) and under 0.5 microgram KI/day (161 +/- 19 micrograms DNA/gland). Reduction of total DNA was independent of TSH, but followed replenishment of the iodine content of the glands. We conclude that TSH mainly induces hypertrophy, whereas thyroid hyperplasia is mainly regulated by the intracellular iodine content.

Rapid method for the direct determination of inorganic iodine in plasma using ion-exchange chromatography and the Sandell and Kolthoff reaction

Abstract: A simple and rapid method for the determination of inorganic iodine in plasma is described. The iodide fraction is separated by means of protein precipitation with ethanol and cation-exchange chromatography. The destruction of the eluted organic matter is carried out by alkaline ashing prior to determination by the Sandell and Kolthoff reaction. Inorganic iodine in plasma at a concentration as low as 3 µg l–1 can be detected in a sample of 0.5 ml.

Mineral content of market samples of fluid whole milk

Abstract: Results from the Food and Drug Administration's Total Diet Study on the nutrient element content of fluid whole cow's milk are presented and compared with previously published values. Whole milk was collected and analyzed yearly from 1975 through 1985. Yearly and overall means were similar for all elements except iron and iodine. The iron content of milk was generally low, but several samples had high levels. The distribution of iodine in whole milk was quite wide (0.002 to 0.094 mg/100 gm). The iodine content of milk is affected by the level of iodine added to cattle feed and by the use of iodophor sanitizing solutions used by the dairy industry. Overall mean levels of the elements in milligrams per 100 gm whole milk were: sodium, 42; potassium, 134; calcium, 106; phosphorus, 83; magnesium, 9.8; iron, 0.07; zinc, 0.37; copper, 0.009; manganese, 0.004; iodine, 0.034; and selenium, 0.001. Coefficients of variation were high (67% to 117%) for iron, copper, manganese, selenium, and iodine but ranged from 18% to 26% for the other elements. An 8-fl oz serving of whole milk is an excellent source of iodine, calcium, phosphorus, and potassium. It also provides some sodium, magnesium, zinc, and selenium but is not a reliable source of iron, copper, or manganese.

Chronic subdural hematomas. Time-density curve and iodine concentration in enhanced CT.

Abstract: Surgery was undertaken on 32 chronic subdural hematomas in a series of 28 patients who had preoperatively undergone delayed contrast-enhanced computed tomography (DCECT). Timedensity curves on DCECT and iodine concentrations of subdural specimens revealed that chronic subdural hematomas, regardless of density, were significantly enhanced by the entrance of intravascular contrast medium into the interior of hematomas. The ingress of intravascular contrast medium into the interior of the hematomas was chemically proven and might result from a complex transcapillary shift.

A phosphorus nuclear magnetic resonance spectroscopic study of the conversion of hydroxy groups into iodo groups in carbohydrates using the iodine–triphenylphosphine–imidazole reagent

Abstract: 31 P N.m.r. spectroscopic studies on the mechanism of the reaction between 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose and the reagent system iodine–triphenylphosphine–imidazole are presented. Three different solvents were tested, toluene–acetonitrile (2:1), acetonitrile, and pyridine. A mechanism is proposed, which is largely consistent with that previously suggested. Imidazole may be replaced by triethylamine, and the reaction also proceeds in pyridine without imidazole or triethylamine. Some features of the equilibrium between triphenyldi-iodophosphorane and iodotriphenylphosphonium iodide (formed from iodine and triphenylphosphine) are also discussed.

Sweet's syndrome: a report on the use of potassium iodide.

Abstract: Summary Eight cases of Sweet's syndrome are reported. Considerable variation in the clinical and the histological features was noted. The effectiveness of potassium iodide is confirmed. This therapy is a useful alternative to systemic steroids.

Abnormal H2O2 supply in the thyroid of a patient with goiter and iodine organification defect.

Abstract: A 71-yr-old man, clinically euthyroid, with a 570-g goiter causing severe mechanical neck compression underwent thyroidectomy. His total serum T4 level was 1.8 μg/dL, T3 was 200 ng/dL, and TSH was 35 μU/mL, and a perchlorate test was markedly abnormal. The excised thyroid tissue had normal peroxidase activity in the tyrosine iodinase and guaiacol assays. [131I]Iodide, given 24 h before surgery, was distributed in thyroglobulin isolated in vitro as follows: monoiodotyrosine, 71.6%; diiodotyrosine, 26.7%; T3,1.05%; and T4, 0.65%. The [131I]iodide content of the whole thyroid homogenate was 59%. The goiter content of thyroglobulin was 94.7 mg/g tissue. The thyroglobulin reacted normally with antihuman thyroglobulin antiserum. Fresh goiter slices and slices from five normal human thyroid specimens were incubated with 10−6 m KI and [131I] iodide (tracer) containing medium alone (basal), medium plus 1 mg/mL glucose oxidase (GO), and medium plus 10−4 m NADPH and 10−5 m vitamin K3 (NA-K3). The percentages of orga...

Use of a prior-oxidation procedure for the determination of iodine by inductively coupled plasma-atomic emission spectrometry

Abstract: A simple prior-oxidation procedure is described for the determination of low concentrations of iodine by inductively coupled plasma-atomic emission spectrometry (ICP-AES) in the ultraviolet and vacuum ultraviolet (VUV) regions of the spectrum. For measuring spectral lines in the VUV region, the monochromator and the enclosed external optical path between the ICP source and the entrance slit of the monochromator have both been purged with nitrogen to minimize oxygen absorption below 190 nm. Iodine atomic emission lines at 206.16 and 183.04 nm have been selected as the analytical lines. The ICP-AES intensity is enhanced by a factor of up to 50 by prior oxidation of the iodide to elemental iodine using several oxidizing additives, presumably because of increased sample-transport efficiency between the nebulizer and the plasma. The best attainable detection limits (3-σ criterion) for iodine at 183.04 and 206.16 nm were 2.00 and 13.9 ng/mL, respectively, in the presence of 3.5-M perchloric acid or 0.2-M hydrogen peroxide, while the corresponding detection limits were 0.088 and 0.56 μg/mL in the absence of an oxidizing additive. The typical analytical working graphs obtained under the optimized operating conditions were rectilinear over approximately five orders of magnitude in concentration.

Process for preparing fluoroaliphatic ether-containing carbonyl fluoride compositions

Abstract: Fluoroaliphatic ether-containing carbonyl fluoride compounds are prepared by reacting a fluorinated carbonyl compound with hexafluoropropylene oxide in the presence of at least one catalyst selected from potassium iodide, potassium bromide, cesium iodide, cesium bromide, rubidium iodide, and rubidium bromide.

Proton and iodine-127 nuclear magnetic resonance studies on the binding of iodide by lactoperoxidase.

Abstract: Interaction of an iodide ion with lactoperoxidase was studied by the use of 1H NMR, 127I NMR, and optical difference spectrum techniques. 1H NMR spectra demonstrated that a major broad hyperfine-shifted signal at about 60 ppm, which is ascribed to the heme peripheral methyl protons, was shifted toward high field by adding KI, indicating the binding of iodide to the active site of the enzyme; the dissociation constant was estimated to be 38 mM at pH 6.1. The binding was further detected by 127I NMR, showing no competition with cyanide. Both 1H NMR and 127I NMR revealed that the binding of iodide to the enzyme is facilitated by the protonation of an ionizable group with a pKa value of 6.0-6.8, which is presumably the distal histidyl residue. Optical difference spectra showed that the binding of an aromatic donor molecule to the enzyme is slightly but distinctly affected by adding KI. On the basis of these results, it was suggested that an iodide ion binds to lactoperoxidase outside the heme crevice but at the position close enough to interact with the distal histidyl residue which possibly mediates electron transport in the iodide oxidation reaction.

Ultrastructure of Sporothrix schenckii treated with iodine-potassium iodide solution

Abstract: The ultrastructural changes produced by iodine-potassium iodide solution on yeast cells of Sporothrix schenckii were investigated by transmission electron microscopy in order to clarify the mechanism of oral potassium iodide therapy for sporotrichosis. Yeast cells were dipped with solutions containing various concentrations of iodine. The rate of germination decreased markedly between the range of iodine concentrations from 0.63 microgram/ml to 5.0 micrograms/ml. No significant ultrastructural changes were seen at the concentration of the iodine of 1.25 microgram/ml (80% germination) or less. In the concentration of 2.5 micrograms/ml (50% germination), normal cells and degenerated cells coexisted. When the cells were treated with 5.0 micrograms of iodine per ml (0% germination) or more, their interior structures were completely destroyed. It is assumed that iodine treatment of the organism causes rapid destruction in the whole cell.

The Iodine Content of Atmospheric Aerosols as Determined by the Use of a Fluoropore Filter® for Collection

Abstract: Atmospheric aerosols were collected onto a Fluoropore filter in order to determine the iodine by means of instrumental neutron activation analysis. The collection filter was found to be the best material among the nine filters examined, for it has the lowest blank values for iodine as well as for other halogens and sodium. The iodine concentrations in Tokyo were found to be 1.7–12.7 ng m−3. Of the soluble iodine, 10% or less was in the form of IO3−.

Organic Iodide Formation During Severe Accidents in Light Water Nuclear Reactors

Abstract: The description of containment iodine behavior in reactor accident sequences involves a combination of iodine volatility effects, deposition/revaporization processes, and mass transport of iodine s...

Physiological aspects of the thyroid trapping function and its suppression in iodine deficiency using 99mTc pertechnetate.

Abstract: In an area of iodine deficiency, we investigated 190 individuals with and without euthyroid endemic goitre, who had a normal TSH response after TRH and an entirely homogeneous thyroid scintigram before and under suppression. In these subjects, the thyroid uptake of 99mTc pertechnetate, as a measure of the iodide trapping function, was determined before (TcUb) and under suppression (TcUs), using quantitatively evaluated scintigraphy. In this control group of individuals, without evidence of autonomy, the reference ranges of TcUb and TcUs were determined. The upper limit of the reference range for TcUb was 7.4% of the tracer activity injected, and for TcUs 1.6%. The reference range of TcUs is to be used to detect accurately thyroid autonomy in vivo. In addition, factors affecting the thyroid trapping function were investigated. With decreased iodine supply, trapping before suppression was increased, compensating for iodine deficiency. The effect of TSH on the trapping function was secondary, indicating that, to a considerable degree, the follicular cells adapt their iodide trapping to the iodine supply. The trapping before and under suppression increased with the estimated thyroid weight. delta TSH after TRH stimulation measured before suppression correlated inversely with the trapping under suppression. The two latter observations suggest that there is a continuum between low and increased levels of the TSH-independent thyroid function, even among these selected individuals without primary evidence of autonomous tissue. A correlation of the trapping function with sex, oestrogen treatment, and goitre type was not demonstrable. Age was found to have a small influence. Except for iodine contamination, the factors affecting the pertechnetate uptake of the thyroid, can be neglected under routine conditions.

A Growth Stimulatory Effect of Iodide Is Suggested by Its Effects on c-myc Messenger Ribonucleic Acid Levels, [3H]Thymidine Incorporation, and Mitotic Activity of Porcine Follicle Cells in Suspension Culture*

Abstract: In the present study the effect of iodide on thyroid cell growth was investigated in primary suspension cultures of porcine thyroid cells capable of organifying iodide. The addition of a high dose of iodide (10-4 M) to such cultures caused a marked increase in c-myc mRNA levels, [3H]thymidine incorporation, and mitotic activity. The incorporation of [3H]thymidine started 30–36 h after the addition of iodide. The stimulatory effect was abolished by a simultaneous incubation with methimazole. The concentration dependence of the iodide-induced stimulation of [3H]thymidine incorporation was similar to that of an inhibitory effect on adenylate cyclase activity. W-7, an inhibitor of calmodulin activity, as well as epinephrine, agents that reduce cAMP levels, also stimulated [3H]thymidine incorporation. Moreover, the stimulatory effect of iodide was reduced in the presence of forskolin. The results suggest that an organic form of iodine stimulates thyroid cell growth by reducing cAMP levels and demonstrate the p...

Radioprotective action of carbimazole in radioiodine therapy for thyrotoxicosis--influence of the drug on iodine kinetics.

Abstract: Pretreatment with carbimazole of patients given radioiodine (131I) therapy for thyrotoxicosis reduces the incidence of early hypothyroidism. The possibility that this radioprotective effect might be a consequence of drug induced alteration in thyroidal iodide turnover, leading to a reduction in thyroid irradiation, was investigated in a prospective study of 24 thyrotoxic patients. Subjects were randomly assigned to receive 131I alone or to be treated with carbimazole for a minimum of three months before 131I. Thyroxine supplements were given in the latter group to prevent iatrogenic hypothyroidism. The effective half-life of therapeutic 131I in the thyroid was measured using a gamma camera/computer system after oral administration of the dose, allowing the biological half life of the anion and estimated radiation dose to the thyroid to be derived. Effective half life of 131I, biological half life of 131I and estimated radiation dose to the thyroid were similar in the two groups of subjects. It is concluded that the radioprotective action of carbimazole is not a consequence of altered thyroidal iodide kinetics.

Effect of iodine intake and methimazole on lymphocytic thyroiditis in the BB/W rat.

Abstract: Spontaneous LT and elevated serum anti-Tg occur in the diabetes prone BB/W rat, but thyroid function is essentially normal in the rats with LT. Prolonged low dose MMI decreases the incidence of LT in BB/W rats. The administration of excess iodine beginning at 30 days of age markedly accelerates the occurrence of LT and anti-Tg at 90 days of age. Low iodine intake decreases the incidence of LT. Excess iodine intake did not induce LT in W-line, Wistar-Furth, and Sprague-Dawley rats. This suggests that iodine induced LT occurs only in genetically susceptible rats. Despite the increased incidence of LT during iodine administration, thyroid function remains essentially normal. This is in contrast to the frequent induction of hypothyroidism following iodine administration to euthyroid patients with Hashimoto's thyroiditis. In order to decrease thyroid reserve, rats were hemi-TX at 30 days of age. The administration of iodine markedly increased the incidence of LT and serum anti-Tg, increased the weight of the remaining lobe, and induced hypothyroidism as determined by significantly lower serum T4 and T3 concentrations and elevated serum TSH concentrations. Excess iodine administration to hemi-TX W-line rats (genetically equivalent, non-diabetes, non-LT prone BB/W rats) did not induce LT but did induce hypothyroidism, suggesting that BB/W and W-line rats are susceptible to iodine induced hypothyroidism, perhaps unrelated to the induction of LT. Excess iodine did not induce LT or affect thyroid function in hemi-TX Wistar-Furth and Sprague-Dawley rats.

Carbamazepine (Tegretol) inhibits in vivo iodide uptake and hormone synthesis in rat thyroid glands.

Abstract: Decreased serum concentrations of T3 and T4 occur in patients treated with the anticonvulsant drug carbamazepine (CBZ), but with rare exception, these patients remain euthyroid. The mechanism that accounts for diminished hormone levels is unknown, and our objective was to study the direct effect of CBZ on iodide uptake and hormone synthesis in thyroid glands of CBZ-treated and pair-fed control rats. Chronic ingestion (per os) of CBZ in male rats reduced the four hour thyroid 131I-iodide uptake by approximately 60%. This inhibition occured after the animals had received sufficient CBZ to attain plasma CBZ concentrations of 0.8 ug/ml. Continued treatment with CBZ ranging from 560 to 800 mg/kg/day for 14 days did not result in further inhibition of iodide uptake even though the plasma CBZ concentrations had increased 6–20 fold. No inhibition of iodide uptake was apparent when the animals initially received CBZ ranging from 40 to 152 mg/kg body weight for 22 days when there were no detectable levels of plasma...

Iodimetric and bromimetric flow injection amperometric methods of determining sulphite in which iodine or bromine is monitored at a glassy carbon electrode

Abstract: A flow injection amperometric method is recommended for the iodimetric determination of sulphite. Both the formation of iodine and its reaction with sulphite are carried out on-line in a single channel manifold consisting typically of 3 m of 0.71 mm bore transmission tubing. Iodine is formed reproducibly in the reverse FIA manner in an injected bolus of dilute acid using a slightly alkaline potassium iodate eluent containing an excess of potassium iodide, and is monitored at a glassy carbon electrode held at –0.2 V vs. SCE, without interference from dissolved molecular oxygen. When acidified sulphite standards or samples are injected into the same eluent a decreased iodine signal is obtained owing to the reaction of the sulphite injected with an equivalent amount of iodine. The decrease in signal size is rectilinear with the sulphite concentration of the injected solution in the range 0.1 × 10–4–4 × 10–4M when injection is made into an eluent 3 × 10–5M in potassium iodate and 0.1 M in potassium iodide.Methods of determining sulphite in which the reaction between iodine or bromine and sulphite is carried out off-line and the excess of iodine or bromine is determined amperometrically by injecting the reacted solution into an inert iodide or bromide eluent, or in which a slightly alkaline sample solution containing iodate-iodide is injected into an acidic eluent, have also been developed.

Self-Diffusion of Sodium, Chloride and Iodide Ions in Acetonitrile-Water Mixtures

Abstract: The self-diffusion coefficient of sodium, chloride and iodide ions in acetonitrile-water mixtures at 25.0 ± 0.05 °C has been measured in dependence on the salt molarity in the range 1.0 ·10-4 1.0 ·10-2 mol/dm3. The ionic self-diffusion coefficients in infinitely diluted solutions have been computed. The influence of the solvent composition on the solvation of the ions is discussed. Preferential solvation of the ions by acetonitrile above 15m ol% of acetonitrile has been found. An effect of the sodium ions on the formation of acetonitrile globules is postulated.