Showing papers on "Iodine published in 1970"

Antithyroid effects of lithium.

Abstract: Lithium has been reported to be goitrogenic when used for the treatment of manic-depressive psychosis. To investigate the effects of lithium on iodine metabolism, male Sprague-Dawley rats were placed on a low iodine (LID) or normal iodine diet (NID) containing enough Li(2)CO(3) to give serum lithium levels of 0.23-0.86 mEq/liter (human therapeutic range is 0.6-1.6 mEq/liter). The following effects were noted with lithium treatment: (a) thyroid weight increased concomitant with a slowing of thyroidal iodine release; (b) the ability to concentrate iodide was increased only after goiters were established; (c) on the LID, (131)I uptake was elevated throughout all phases of treatment, even when the release rate was normal; (d) iodine organification was unaffected but the proportion of (131)I present as iodothyronines was decreased; (e) the thyroidal (127)I content was increased; (f) despite these changes, the serum PBI remained normal as did the thyroxine turnover rate; and (g) thyrotropin (TSH) levels in serum were the same as controls except for a slight elevation early in the course of treatment; TSH levels did not correlate with goitrogenesis. When LiCl was injected in large doses into intact rats (giving serum lithium levels of 3.08-3.89 mEq/liter), the iodide concentrating mechanism, (131)I uptake, and (131)I release rates were depressed. Similar experiments in hypophysectomized rats receiving TSH demonstrated these to be local antithyroid effects not mediated through the pituitary. The discrepancy between acute and chronic responses to lithium, and the dissociation between the inhibition of iodine release and stimulatory effects is discussed.

Inhibition by iodine of the release of thyroxine from the thyroid glands of patients with thyrotoxicosis

Abstract: A method has been devised which is free of many of the shortcomings of serial epithyroid counting techniques as an index of the rate of thyroid hormone secretion. By means of this method, the effect of treatment with Lugol's iodine on the rate of thyroidal secretion of thyroxine (T(4)) has been assessed in eight patients with thyrotoxicosis due to diffuse or multinodular goiter. The technique involves administration of a tracer dose of inorganic (125)I followed several days later by an intravenous tracer dose of (131)I-labeled T(4). Serial observations of serum protein-bound (PB) (125)I and (131)I are accompanied by frequent measurements of endogenous serum T(4) (T(4)-(127)I) concentration. Regardless of whether or not its administration was anteceded and accompanied by the administration of large doses of methimazole, iodine induced a rapid decrease in serum T(4)-(127)I concentration which could not be explained by an increase in the peripheral turnover of T(4), as judged from the metabolism of the (131)I-labeled hormone. Hence, the decreased serum T(4) concentration could only have resulted from decreased secretion of the hormone by the gland. Analyses of specific activity relationships between PB(125)I or T(4)-(127)I and PB(131)I made possible estimations of the extent to which iodine had decreased the rate of secretion of T(4). From such analysis, and in view of other considerations, it is concluded that the rapid decrease in T(4) secretion induced by iodine is not the result of an acute, sustained inhibition of T(4) synthesis, but rather results from an abrupt decrease in the fractional rate of thyroidal T(4) release.

Solid state lithium-iodine primary battery

Abstract: A substantially anhydrous solid state battery has a lithium anode, a solid lithium iodide electrolyte and an electronically conductive cathode containing iodine, such as organic iodine charge transfer complexes.

Significance of iodide-perchlorate discharge test for detection of iodine organification defect of the thyroid.

Abstract: Perchlorate tests were performed after oral administration of radioiodine without carrier iodide (conventional perchlorate test) or with 500 μg of 127I (iodide-perchlorate test). In neither test was there a significant discharge of 131I in control subjects. In subjects treated with l-methyl-2-mercaptoimidazole positive discharge was observed with the iodide-perchlorate test, but not with conventional perchlorate test. Of 8 patients with Hashimoto's thyroiditis, only 2 showed positive discharge tests by the conventional perchlorate test, whereas the iodide-perchlorate test was positive in all these patients.

The crystal structures of three alkali-metal complexes with cyclic polyethers

Abstract: The crystal structures are reported of sodium bromide with a 6-oxygen cyclic ether, sodium iodide with a 5-oxygen cyclic ether, and potassium iodide with a 10-oxygen ether; in the first two the cation is co-ordinated by additional entities but the 10-oxygen compound encloses the potassium completely

A new method for the measurement of thyroidal iodine release in man

Abstract: A new method is described for the detection of variations in the release rate of all iodinated products by the thyroid gland in man. (125)I was employed to endogenously label the thyroid gland, and a parenterally administered (131)I thyroxine dose was used to generate a (131)I reference source. Thyroidal iodine release activity was quantitatively assessed by the measurement of variations in (125)I/(131)I ratio values obtained in timed urine samples. Diurnal variation in thyroid release patterns was observed in euthyroid subjects which was promptly suppressed by exogenous triiodothyronine administration and was simulated by the intramuscular injection of 0.25-0.50 U of bovine thyrotropin. The zenith value occurred at 4:00 a.m. +/-3.4 hr (SD) and the nadir at 5:00 p.m. +/-3.6 hr. The absence of a diurnal pattern in patients with thyrotoxicosis and in secondary hypothyroidism indicated that this diurnal fluctuation was under thyrotropin (TSH) regulation. This new method also promises to be a useful tool for the study of the intrathyroidal recycling of iodide from the iodotyrosine pool and the detection of factors which may acutely alter thyroid function.

Effects of Iodide on Thyroid Stimulation

Abstract: Iodide directly inhibits thyrotropin (TSH)- or long-acting thyroid stimulator (LATS)-stimulated thyroid hormone release To investigate the mechanism (s) of iodide inhibition we studied the effects of iodide on adenyl cyclase activation, colloid droplet formation and glucose-1-14C oxidation in sheep thyroid in vitro Nal alone, 10−5 to 10−3m, consistently stimulated adenyl cyclase, had a marginal stimulatory effect on glucose oxidation, but did not augment colloid droplet formation The stimulatory effects of TSH and prostaglandin E1 (PGE1) on adenyl cyclase and glucose oxidation and of dibutyryl cyclic-AMP (DBC) on glucose oxidation were inhibited by excess iodide but TSH, PGE1 and DBC stimulation of colloid droplet formation was unaffected The stimulatory and inhibitory effects of Nal on adenyl cyclase activation and slice metabolism were abolished in the presence of methimazole, 10−4m, in the incubation medium Twenty-four hr of KI pretreatment markedly inhibited the effects of TSH, LATS, PGE

Positronium and Iodine Reactions in Organic Solvents

Abstract: The quenching of o‐Ps by iodine in various organic solvents is investigated. It is found that iodine acts as both a chemical quenching agent and a Ps formation inhibitor. The reaction between Ps and iodine is diffusion controlled. The annihilation lifetime of the formed Ps iodine compound (PsI2 or PsI) is estimated to be 0.4 nsec. The inhibition coefficient is calculated to be 20 mole−1 for iodine in hydrocarbon solvents and 5.0 mole−1 in oxyhydrocarbon solvents. After an investigation the high Ps quenching rates in iodine solutions cannot all be attributed to high values of the diffusion coefficient. The interaction between Ps and iodine must also be taken into consideration. Obviously, the formation of the charge‐transfer complex of iodine plays an important role here.

Iodine and Thyroxine Metabolism in Anephric Patients Receiving Chronic Peritoneal Dialysis

Abstract: Iodide and thyroxine metabolism were studied in 5 renoprival patients undergoing chronic, weekly peritoneal dialysis as they were awaiting renal transplantation. The subjects were studied on a clinical research ward after equilibration for a 10- to 13-week period to the hospital diet. Each was dialyzed for approximately 1½ days weekly. Radioiodine kinetic studies conducted during the interval between dialyses indicated that the radioiodine distribution space and the thyroidal uptake rate constant were similar to values in normal subjects. The fecal excretion of iodide and iodide losses in saliva and sweat were increased somewhat. Mean iodine intake and calculated daily thyroidal iodide accumulation were similar to values in normal Arkansas residents. Iodide excretion in the dialysis fluid approximated that normally observed in the urine. Radiothyroxine kinetic studies indicated normal thyroxine distribution and normal fractional thyroxine degradation. Daily thyroxine turnover was significantly ab...

Plasma TSH Levels in Endemic Goiter Subjects

Abstract: Plasma TSH levels were measured in goitrous young males living in an area of moderate iodide deficiency in the Egyptian desert (New Valley). Nongoitrous young males living in an area of the same desert where water iodide concentrations were higher (Siwa oases) and a group of normal American subjects served as controls. Plasma TSH levels were higher in the New Valley males than in either control group. Serum PBI values and urinary iodide excretions were lower in the goitrous New Valley subjects than in the Siwa controls. These data support the hypothesis that, at least in some instances, an increase in circulating TSH is a contributing factor to endemic goiter formation in subjects living in areas of mild to moderate iodide deficiency.

Radio-sensitization with Iodine Compounds: I. Examination of Damage in Deoxyribonucleic Acid with Bacillus Subtilis transformation system by irradiation in the presence of potassium iodide

Abstract: SummaryTo study whether radiation sensitization with iodine compounds, such as potassium iodide (KI), potassium iodate (KIO3) or iodoacetic acid (ICH2 · COOH), involves increased damage to DNA, studies have been carried out on the transformation system of Bacillus subtilis. Radiation-sensitizing effects, especially marked at low pH, were observed when bacteria were irradiated in the presence of these agents. When transforming DNA was irradiated in vitro, the inactivation of genetic capacity was greatly protected by the addition of KI. This protective effect was also found in the radiolysis of four DNA bases dissolved in water. When DNA was extracted by the phenol method from irradiated cells and the transforming capacity measured, no remarkable difference was observed as to the arginine marker, whether bacteria sensitized by KI or not when irradiated. Alkaline-sucrose gradient studies showed that the number of single-stranded breaks from irradiated cells was not enhanced by the addition of KI during irrad...

Effect of Iodide on Thyroidal Iodine Turnover in Hyperthyroid Subjects

Abstract: Quantitative studies of iodine metabolism were carried out in iodide-treated hyperthyroid patients in order to observe the alterations of iodine metabolism which occur in response to clinical improvement and to the recurrence of symptoms. Twelve hyperthyroid patients were given 10 mg of iodide as KI t.i.d. and several thyroid function tests were performed at intervals of 2 weeks thereafter. Serum PBI and T3-resin sponge uptake decreased to the normal range within 2 weeks in all patients and these normal values continued until recurrence of thyrotoxicity. One, 2 and 24 hr thyroidal 131I uptakes decreased from 57.4 to 22.6%, from 68.0 to 24.4%, and from 75.1 to 19.9%, respectively, within 2 weeks of the iodide treatment. However, these values were considerably higher than those obtained from similarly treated euthyroid subjects (2.6, 2.5 and 3.4%, respectively). Thyroidal absolute iodine uptake (AIU), calculated from thyroidal clearance of 131I multiplied by serum inorganic 127I, increased about 3-...

The Nature of Inhibition of Mitochondrial Malate Dehydrogenase by Thyroxine, Iodine Cyanide and Molecular Iodine

Abstract: The mechanism of inhibition of the enzyme activity of mitochondrial malate dehydrogenase by thyroxine, iodine cyanide and molecular iodine has been further investigated. The results obtained allow us to exclude formation of a protein/inhibitor stable complex, iodination of the enzyme or disaggregation of the protein molecule into inactive subunits as explanations for the enzyme inactivation induced by the iodine-containing compounds. On the other hand, it has been demonstrated that in all cases the enzyme inhibition is dependent on the oxidation of certain—SH groups necessary for the activity. Direct oxidation of the thiol groups of the protein by molecular iodine and iodine cyanide can be easily assumed, whereas the chemical mechanism of the thyroxine-induced enzyme inactivation is harder to explain. However, since neither hormone deiodination nor metal chelation occur, while thyroxine by itself is also able to oxidize the thiol group of reduced glutathione, a direct effect of thyroxine on the sulfhydryl groups of the enzyme is postulated.

Thyroidal iodine and proteins in autoimmune thyroiditis.

Abstract: The iodine content of thyroid tissue from patients with autoimmune thyroid itis was determined in 10 cases. The concentration was usually below 60 μg/g of tissue wet weight and the total content below 4000 μg. The thyroidal proteins were studied in 8 patients. In four thyroglobulin formed from 25 to 52 per cent of the thyroid proteins. Two patients who had the lowest iodine content were hypothyroid. There is a correlation between the decrease in thyroglobulin, the decrease in iodine content, and the appearance of clinical hypothyroidism.

Chemical consequences of the auger effect: iodine yield from iodoamino acids as a function of x-ray dose and energy.

Abstract: Absorption of x-radiation in the iodothyronines results mainly in deiodination. G-values and dose effect curves were determined from 0.5 to 3.0 Mrads total absorbed dose for 3,5-diiodo-DL-thyronine, 3,5,3′-triiodo-DL-thyronine, and thyroxine. Radiation sensitivity increases with decreasing number of iodine atoms per molecule. Calculations based on I2 yield measurements, as a function of maximum x-ray energy, indicate (after correction for radiation dose) that resonance absorption has a distinct effect upon the ensuing chemical transformation. This effect is stronger than would be predicted from published values of the K-to-L-shell Auger yields in iodine.

The oxidation of reduced nicotinamide nucleotides by hydrogen peroxide in the presence of lactoperoxidase and thiocyanate, iodide or bromide

Abstract: Lactoperoxidase (EC 1.11.1.7) catalysed the oxidation of NADH by hydrogen peroxide in the presence of either thiocyanate, iodide or bromide. In the presence of thiocyanate, net oxidation of thiocyanate occurred simultaneously with the oxidation of NADH, but in the presence of iodide or bromide, only the oxidation of NADH occurred to a significant extent. In the presence of thiocyanate or bromide, NADH was oxidized to NAD+ but in the presence of iodide, an oxidation product with spectral and chemical properties distinct from NAD+ was formed. Thiocyanate, iodide and bromide appeared to function in the oxidation of NADH by themselves being oxidized to products which in turn oxidized NADH, rather than by activating the enzyme. Iodine, which oxidized NADH non-enzymically, appeared to be an intermediate in the oxidation of NADH in the presence of iodide. NADPH was oxidized similarly under the same conditions. An assessment was made of the rates of these oxidation reactions, together with the rates of other lactoperoxidase-catalysed reactions, at physiological concentrations of thiocyanate, iodide and bromide. The results indicated that in milk and saliva the oxidation of thiocyanate to a bacterial inhibitor was likely to predominate over the oxidation of NADH.

Electron staining of synaptic vesicles using the Champy-Maillet technique

Abstract: SUMMARY Synaptic vesicles from rat pineal nerves can be stained by Champy-Maillet mixtures containing osmium tetroxide and a soluble iodide. Two components of the vesicle (the matrix and the dense core) are revealed in a different way depending on at least two factors: the iodide employed and the final pH of the mixture. We have tried the following mixtures: zinc iodide at pH 5·5 (ZIO), cadmium iodide at pH 6·0 (CIO) and potassium iodide at pH 7·2 (KIO-7) or pH 5·5 (KIO-5). The matrix is more reactive with ZIO, while the dense core is more reactive with CIO and especially with KIO-7. With the only difference of a lower pH, KIO-5 stains the whole matrix of some vesicles and also reveals some tubular structures which are more frequently found in preterminal axons.

Thyroxine Biosynthesis in Human Goitrous Cretinism

Abstract: Three adult goitrous cretin siblings were studied to determine the biochemical deficiency that resulted in depressed thyroidal thyroxine biosynthesis. Their thyroids could effectively transport and oxidize iodide and iodinate and deiodinate iodotyrosines. The glands had an adequate content of proteolytic enzymes for the release of free iodoamino acids. Thsse patients had a defective mechanism for synthesizing iodothyronines although there were no deficiencies in 2 enzymes, peroxidase and iodotyrosine transaminase, which have been implicated in the so-called coupling reaction. The serum protein bound iodine was normal but only ⅓ of this iodine was soluble in butanol, indicative of an abnormal iodopeptide or iodoprotein in the serum. Analysis of the iodoprotein composition of the cretin glands by salt fractionation, DEAEcellulose chromatography, radioimmunoelectrophoresis and sucrose gradient centrifugation revealed that there were only small amounts of thyroglobulin in the tissue. Some iodine was ...

Fluorometric Method for Determination of Mercury (II) with Rhodamine B

Abstract: Mercury (II) is able to quench the fluorescence of Rhodamine B in the presence of potassium iodide. The quenching was affected by pH of the solution and the concentration of potassium iodide, but not markedly by several anions. The degree of quenching was closely correlated with mercury (II) concentrations at the fixed concentrations of the dye and potassium iodide, so that mercury (II) can be fluorometrically determined in this method. Cystline and egg albumin protected the quenching by mercury (II) in the presence of potassium iodide. The fluorescence of Rhodamine B was not quenched by organic mercury (II) compounds in the presence of potassium iodide. Fluorescence of the dye was also quenched by some metal ions, such as bismuth (III), thallium (III), palladium (II) and platinum (IV) in the presence of potassium iodide.

The nitration of iodoimidazoles

Abstract: Treatment of iodoimidazoles with nitric acid of various concentrations results in replacement of the iodine atoms by nitro groups, including those in the 2-position, which is not activated towards electrophilic substitution in acid media. The use of a nitric acid- sulfuric acid nitrating mixture also results in the replacements of the iodine atom in the 4(5)position.

Color Reactions of Poly vinyl Acetate and Its Derivatives with Iodine

Abstract: It has been found that the addition of a methanol solution containing polyvinyl acetate (PVAc) and iodine to an aqueous solution of potassium iodide results in a red-violet color without precipitating any polymer. The absorption maximum was located at 510 mμ. The absorbance of the PVAc-iodine complex decreased only slightly with an increase in the degree of the polymerization of PVAc. A linear relationship was obtained between the abosrbance and the PVAc concentration. It was found from these results that the color reaction of PVAc with iodine can be used in a colorimetric determination of PVAc, which is insoluble in water. Further, an attempt was made to investigate the complex formation of the vinyl acetate-vinyl propionate copolymer (PVAc-PVPr) and the vinyl acetate-vinyl formacetal copolymer (PVAc-PVFA) with iodine. Although the absorption maximum of the color complex of PVAc-PVPr with iodine appeared at 510 mμ, independent of the copolymer composition, the absorbance decreased with an increase in the...

Dispersions of Metastable High Temperature Cubie Silver Iodide

Abstract: The crystalline forms of silver iodide are reviewed. By means of double-jet precipitation using gelatin, at 70 °C with a carefully controlled excess of potassium iodide (pl=2-2.5) or silver nitrate (pAg 2-4), bright yellow dispersions are obtained which change to ordinary cream coloured silver iodide slowly upon keeping or instantly upon cooling to 27°C. By means of quantitative measurements of the blue shift of the reflection spectrum, of the volume change on transition, and of X-ray diffraction powder patterns, the presence of the high temperature (> 146°C) form of silver iodide in these dispersions is established.