Showing papers on "Iodine published in 1974"

The influence of organic matter, chalk, and sesquioxides on the solubility of iodide, elemental iodine, and iodate incubated with soil

Abstract: Summary Iodine in each of the forms iodide, elemental iodine, and iodate was added, at a rate of 5 mg/kg to a sandy loam and to mixtures of the soil with composted grass roots, chalk and sesquixoides, and its solubility determined after various periods of incubation. With iodide, solubility in both 0.01 M CaCl2 and 1.0 M NK4 acetate (pH 4.8) declined rapidly over the period o to 3 days and subsequently reached approximate equilibrium levels of 2.8 per cent solubility in CaCl2 and 7.8 per cent in NH4 acetate, these values being the means of samples incubated for 48, 103, and 160 days. The partial (5 per cent) replacement of the soil by composted grass roots had no appreciable effect on the solubility of added iodide, while chalk, incorporated at a rate of 5 per cent, depressed the solubility of iodide in CaCl2 to 1.8 per cent but caused a slight increase in solubility in NH4 acetate. The incorporation of 2 per cent hydrated ferric oxide or of 2 per cent hydrated aluminium oxide reduced the solubility of iodide in CaCl2 to 0.1 and 0.3 per cent, and in NH4, acetate to 3.8 and 5.7 per cent respectively. Elemental iodine was similar to iodide in its solubility in the two extractants and in its response to the various soil treatments. Iodate, however, differed considerably from the other two forms of iodine. With soil alone, and with the soil/chalk mixture, its decline in solubility with increasing incubation time was relatively slow, although after 160 days its solubility was similar to that of iodide and elemental iodine. The incorporation of composted grass roots caused a rapid reduction in iodate solubility, suggesting that the organic matter accelerated the reduction of iodate to elemental iodine or iodide. With the treatments involving the incorporation of ferric and aluminium oxides, there appeared to be considerable sorption of iodate during the 16 h extraction period and the effects of these materials on iodate solubility during incubation were therefore difficult to assess.

A model of iodine kinetics in the dog.

Abstract: A composite mathematical model of iodine kinetics in the dog was developed by combining representative models of the component subsystems: iodide, T3, T4 and the thyroid gland. Blocking of thyroidal uptake with stable iodine permitted the study of each subsystem independently. The iodide subsystem includes early and late distributional phases in addition to urinary and fecal excretion pathways. The T3 and T4 subsystems are each represented by two metabolic compartments and pathways for deiodination and fecal excretion. The thyroid is represented by two compartments, corresponding to rapid and slow secretory phases. Both tracer and steady state tracee data were used in the calculations. Rates of exchange, coupling coefficients, masses, concentrations and spaces of distribution were calculated by the SAAM computer program. The kinetics of hormone distribution and turnover and thyroidal iodine turnover are more rapid in the dog than in man. The only not able exception is the rate of urinary excretion of iodi...

Labeling of thyroid hormones and their derivatives.

Abstract: A method is described for radioiodinating thyroxine, 3,5,3'-triiodo-L-thyronine, tetraiodothyroacetic acid and 3,5,3'-triiodothyroacetic acid with 125I-iodide, using chloramine-T as an oxidant. With appropriate conditions, this oxidizing agent permits a gentle and reproducible radioiodination of these compounds. Separation of the labeled compounds from the non-reacted Na125I can be achieved with a Sephadex LH-20 column or by paper chromatography. Their specific specific activities were measured by competitive protein-binding assays. The method permits both substitution of radioactive for stable iodine in the parentcompound and, in the case of triiodinated compounds, addition of radioactive iodine to the molecule to yield the tetraiodinated compounds. The latter method produces compounds of very high specific activities.(Endocrinology 94: 1189, 1974)

A Radiation-Induced Bonding of Iodine at the Surface of Uniform Polystyrene Particles

Abstract: At a population of 1.4 X 1012 particles of 0.234-um diameter cc-', the yield of surfacebonded halogen in 5 X 10-4 M iodide corresponds to 0.02 iodine atoms bonded to the particle surface per 100 eV of total energy absorbed. In 5 X 10-4 M iodide, the reaction rate is proportional to the surface area and depends upon the first power of the radiation intensity. The experimental results are consistent with a reaction mechanism in which radical sites are produced on the particle surface by reaction of OH and other radicals from the bulk phase. A surface bonding of iodine results from a reaction of these sites with halogen intermediates formed in the aqueous phase, predominantly by reaction of OH radicals with iodide. Energy absorbed in the particle apparently plays no major role in the reaction, and a complex dependence of the reaction upon the iodide concentration suggests that a surface adsorption of halogen intermediates plays an important role in the reaction.

A method for determining iodine-129 in milk and water.

Abstract: An analytical method for determining sup 129/I in environmental milk and water samples is described. The method depends on the specificity of elemental iodine separation by solvent extaction, followed by liquid scintillation counting of the lowenergy beta emissions from /sup 129/I. Iodine, as iodide, is concentrated by sorption on an anion exchange column and eluted with NaOCl. After reduction to I/sub 2/, the iodine is extracted into CCl/sub 4/, back extracted into water, cleaned by one toluene-water extraction cycle, and finally extracted into toluene. Chemical recovery of the added carrier is determined spectrophotometrically on a small aliquot of the toluene extract. The /sup 129/I concentration is determined by liquid scintillation counting of the toluene solution. Average % recovery of iodine carrier is 74 plus or minus 2 for water 58 plus or minus 3 for raw milk, and 80 plus or minus 4 for pasteurized milk. Analytical sensitivity is 0.3 pCi /sup 129/I/l. for a 4 -- 1. sample. (auth)

A Defective Thyroid Peroxidase Solubilized from a Familial Goiter with Iodine Organification Defect

Abstract: A 25-yr-old woman with no clinical hypothyroidism had a goiter since childhood. Her mother and first cousin also had goiters. 33% of the thyroidal iodine was released by perchlorate indicating a partial iodine organification defect. Plasma thyroxine as well as the concentration inorganic iodide were very low. Thyroid iodine uptake was very high. The thyroid tissue obtained at thyroidectomy contained a high concentration of thyroid peroxidase (I2 formation from I−, when tested after solubilization of the enzyme by trypsin and digitonin treatment of the particulate material. 1. The enzymatic activity behaved on DEAE column chromatography exactly as those of hog or sheep. Its sedimentation coefficient (5.5 S) and molecular weight (97,000) were almost identical to those of the hog enzyme (5.2 S and 103,000). 2. Both hog and goiter enzyme catalyzed iodide peroxidation (I− → I2) and gaiacol oxidation to tetragaiacol. The km (iodide) values (3 × 10−3m) were almost identical for the two enzymes; km (gaia...

Potassium iodide chemiluminescence in diffusion flames and the KI upper-state potential

Abstract: Chemiluminescence spectra of potassium iodide have been measured in a dilute diffusion flame apparatus. A total of 54 fluctuation bands have been resolved. An analysis of these results as well as previous potassium iodide spectra is presented. By using molecular beam scattering data an extremely accurate excited state potential for potassium iodide is obtained.

Influence of Perchlorate on the Secretion of Non-Thyroxine Iodine by the Normal Human Thyroid Gland

Abstract: . Several authors have postulated that endogenous iodide produced by the deiodination of iodotyrosines in the thyroid feeds into a different thyroidal iodide compartment than transported iodide which enters the gland from outside. One argument for the existence of two separate iodide compartments is the observation that under certain experimental conditions perchlorate completely discharges transported iodide from the thyroid, while it has no such effect on endogenous iodide. This latter observation however has not been confirmed by all studies and remained controversial. – We therefore reinvestigated the effect of perchlorate on the secretion of endogenous iodide by a new, sensitive method. Five normal volunteers received tracer amounts of iodide-125I p.o. and 11 days later thyroxine-131I I.V. Two days later the following serial measurements were started: serum protein-bound labelled iodine (PB125I, PB131), serum total thyroxine and urinary excretion of 125I, 127I and 131I. – In the control period the non-thyroxine iodine secretion calculated from the above measurements was 40 μg/day. Under perchlorate 200 mg three times daily this value rose significantly to 66 μg/day. Non-thyroxine iodine comprises the secreted triiodothyronine plus the secreted endogenous iodide. Assuming that the former value remained constant, our data show that perchlorate indeed discharges part, though not all, of the endogenous iodide. These data do not rule out a second iodide compartment, but they are also compatible with a simple one compartment model.

Interaction of polyvinylpyrrolidone and iodine

Abstract: A nonsolvent preparation of the polyvinylpyrrolidone (PVP) complex provides new insight into the nature of the polymer-iodine interaction. The preparation is obtained by simply mixing PVP with crystalline iodine and is of interest because it provides a system in which no interfering ions are present and only one type of iodine is initially present. The iodine is shown to undergo hydrolysis with moisture in the polymer to give iodide and hypoiodite. The ionic forms of iodine appear to associate with the molecular iodine, resulting in the final stable PVP-iodine complex.

Polyvinylpyrrolidone-iodide compositions and polyvinylpyrrolidone-iodide-iodine complexes prepared therefrom

Abstract: A unique PVP-iodide solid solution is prepared by drying a solution of PVP and iodide wherein the PVP:I ratio is preferably in the range of about 2:1 to 6:1, which dried product may then be mechanically blended with elemental iodine at ambient temperature to rapidly form a stabilized PVP-iodide-iodine complex, characterized in that the resulting product comprises a single solid phase.

Iodine recovery process

Abstract: Iodine is recovered from an aqueous solution containing iodide such as underground brine by repeated cycles of (1) passing the brine through a basic anion exchange resin to adsorb iodide, and (2) oxidizing adsorbed iodide to iodine by passing an acidified aqueous iodate solution (e.g., NaIO 3 ) through the resin. The cycle is repeated many times until the resin is iodine-loaded. Iodine is then eluted from the resin, for example, with aqueous NaOH and recovered from the eluate by conventional means.

Effects of Fatty Acids on the Interaction of 1-Anilino-8-naphthalenesulfonate with Human Plasma Albumin

Abstract: The fluorescence of 1-anilinio-8-naphthalenesulfonate (ANS) bound to human plasma albumin was enhanced when up to 2 moles of palmitate were added. Larger amounts of palmitate produced a progressive reduction in ANS fluorescene. Saturated and unsaturated fatty acids containing 14-18 carbon atoms produced similar biphasic effects on ANS fluorescence with human albumin. Fatty acids containing 10-12 carbon atoms produced only a reduction in ANS fluorescence, and those containing 2-8 carbon atoms had no effect. Similar results were obtained with canine albumin, whereas with bovine and rabbit albumins, fatty acids in all concentrations reduced ANS fluorescence. The tryptophan fluorescence of human albumin was decreased markedly by ANS, but not by palmitate. However, palmitate partially protected the tyrptophan fluorescence against quenching by potassium iodide. Equilibrium dialysis measurements indicated that ANS binding to human albumin was reduced when 3 or more moles of long-chain fatty acid were added per mole of albumin, suggesting that the decrease in ANA fluorescence produced by high concentrations of fatty acid was due to displacement of ANS from albumin. ANS binding was essentially unchanged when 1 or 2 moles of fatty acid were present. Therefore the enhancement in ANS fluorescence produced by low concentrations of fatty acid appears to result from a change in the interaction of ANS with albumin rather than from an increase in the amount of ANS that is bound The data obtained with this fluorescent model compound suggest that the binding of some drugs to albumin may be influenced by changes in the plasma free fatty acid concentration. Small increases, such as those which occur under ordinary physiological conditions, are likely to alter the molecular interactions between albumin and the drug without appreciably affecting the strength of drug binding. When the molar ratio of fatty acid to albumin approaches 3, however, a decrease in drug binding is likely to occur.

The Relationship Between Thyroglobulin Synthesis and Intrathyroid Iodine Metabolism as Indicated by the Effects of Cycloheximide in the Rat

Abstract: The effect of small doses of cyclohex-imide (CH) (0.5 µg/g body wt) on the intrathyroid metabolism of carrier-free 13II and stable iodide iniodine-sufficient and iodine-deficient rats and on thyroglobulin (Tgb) maturation in iodine-deficient rats was studied. This dose of CH had no apparent toxicity but strikingly inhibited the incorporation of l4C-labeled amino acids into thyroid and plasma proteins. In iodine-sufficient rats, CH did not affect T/S (I−) ratios, but did enhance the sensitivity of the thyroid to the acute inhibitory effects of stable iodide on the organification mechanism (Wolff-Chaikoff effect). CH produced unusual effects on the intrathyroid metabolism of 131I in these iodine-sufficient rats: a decrease in 13II uptake, an increase in labeled DIT and a decrease in MIT so that MIT/DIT ratio declined, and a decrease in the proportionate synthesis of the iodothyronines T4 and T3. In iodine-deficient rats, CH also sensitized) the thyroid to the acute Wolff-Chaikoff effect but produced changes...

Pyrroles and related compounds. Part XXVIII. β-Keto-esters in the porphyrin series

Abstract: Porphyrin carboxylic acids are converted into the corresponding β-keto-esters by reaction between the acid chlorides and t-butyl methyl malonate, followed by treatment with trifluoroacetic acid. Iodine in methanol reacts with the magnesium chelate of the keto-ester anion derived from rhodoporphyrin-XV dimethyl ester, giving the chelate of 10-methoxyphaeoporphyrin-a5 dimethyl ester. The significance of these results in relation to the biosynthesis of chlorophyll is discussed.

The Iodination of Benzene with Iodine in the Thallium(III) Trifluoroacetate-Trifluoroacetic Acid System

Abstract: Molecular iodine in the system of thallium(III) trifluoroacetate-trifluoroacetic acid has been found to possess a high potency for aromatic iodination. Under controlled conditions, benzene and also mesitylene were stepby-step mono-, di-, and triiodinated, whereupon whole iodine was consumed for the iodination by the oxidation process of the thallium(III) salt. In the course of the iodination of benzene, an intermediate has been revealed to consist of thalliated benzenes, which were transformed into iodinated benzenes by the electrophilic attack of iodine.

Iodide sialadenitis in childhood.

Abstract: When the external genitalia of these two fetuses were examined, the urethral orifice was still on the under-surface of the penis, while in fetuses of crown-rump length of 8 cm it had approached the tip of the glans. The mean plasma testosterone concentration of the 6 fetuses with crown-rump length of 8 cm was 302 ng/100 ml, range 252-379 ng/100 ml. In fetuses of crown-rump length of 10 cm or longer, the urethral orifice appeared to be in the normal adult position. These results confirmed those of Glenister (1954).

Effects of Pharmacological Doses of Iodide on the Hyperplastic Rat Thyroid Gland. Roles of Intrathyroidal Iodide, Thyrotropin and Thyroglobulin in the Wolff- Chaikoff Phenomenon11

Abstract: The block of organic iodine formation by excess iodide was reinvestigated, paying particular attention to the intrathyroidal iodide concentration, to the role of TSH and to changes in physicochemical properties of thyroglobulin. Maximal TSH stimulation was obtained by pretreating rats for 4 weeks with propylthiouracil followed by 2 days of a low-iodine diet. Three mg iodide was then injected every 12 hr and the thyroid glands were analyzed at daily intervals. The initially very high intrathyroidal iodide concentration decreased rapidly during the first 4 days of excess iodide, irrespective of whether TSH was high or suppressed by thyroxine injections. Thus TSH played only a minor part in the adaptation of the active iodide transport mechanism. Organic iodine formation was blocked during the first 4 days of iodide treatment. As soon as the intrathyroidal iodide fell below 0.1 μg per mg tissue, organic iodination resumed in TSH-stimulated glands. In animals with low TSH the escape from the block was delayed...

Detection Systems for the Low Level Radiochemical Analysis of Iodine-131, Iodine-129 and Natural Iodine in Environmental Samples

Abstract: A procedure based on chemical separation techniques and activation analysis has been developed for the sequential analysis of low levels of 131I, 129I and natural iodine in environmental samples. The iodine is first separated from the samples by oxidation. The separated iodine is then counted by low level, beta-gated gamm-jay spectrometry for the measurement of 131I. The chemical yield for the separation is measured by means of 125I tracer. Activation analysis is used for measurement of the separated natural iodine (127I) and 129I. The natural iodine is estimated from either the 126I or 128I activity produced in the sample. the induced 130I is used to estimate the 129I concentration. The measurement of 130I at low levels requires specialized counting methods. Interfering activities which may be present in the irradiated sample include 125I, 126I, shortlived fission-product iodine activities produced by activation of uranium impurities, and 82Br from bromine impurities. Since 130I decays with several coincident gamma-rays, multiple gamma-ray coincidence counting techniques can be used to reduce background and discriminate against interfering activities. Sevoral three-and four-segmented NaI(Tl) detectors have been used for these measurements and compared with other detector systems. The sensitivities for different coincidence counting modes were compared for several of the detector systems. Detection sensitivities-achieved for 131I and 129I are 0.02 dpm and 10-6 dpm, respectively. Measurements have been made of iodine radioactivity in the environment at concentrations below the limits established for radiation protection purposes.