Total Iodine Content Research Articles

Salivary secretion of iodine after urography. Further evidence for in vivo deiodination and salivary secretion of contrast media.

Salivary concentrations of total iodine and iodide of patients with and without renal insufficiency have been measured after injection of urographic contrast media. The results support the hypothesis of in vivo deiodination of urographic contrast materials under certain conditions and also indicate that these contrast media are secreted in the saliva in small amounts. Low concentrations of inorganic, presumably unbound iodide have been detected regularly in bottled contrast media, but these amounts are probably small compared to that resulting from in vivo deiodination.

Fluorescent excitation analysis: a simplified method of iodine determination in vitro.

Iodine concentrations in bile, serum, and urine were determined by fluorescent excitation analysis using Americium-241 as the excitation source. The number of characteristic photons produced by the interaction of the exciting radiation with the iodine K-shell elecrons was directly related to concentration of iodine in the unknown sample. This method measured total iodine concentration directly in mg/ml and was accurate to ± 2% over an iodine concentration range of .2 to 50 mg/ml. This method does not require the purchase, handling, or disposal of radioactive material.

The content of thyroid hormones and other iodinated compounds in thyroid tissue in autoimmune thyroiditis.

ABSTRACT The total iodine content and the content of iodocompounds in the thyroid gland were studied in 9 patients with autoimmune thyroiditis. The thyroids were labelled in vivo with radioactive iodine before surgical biopsy. Five grams of tissue were homogenized and the iodocompounds were separated both by paper chromatography and on a cellulose column. The distribution profile of both the radioactive and the stable compounds was determined. The thyroid tissue contained on an average 11.0 ± 8.0 (sd) per cent of radioactive and 15.0 ± 9.4 per cent of stable iodothyronines. The MIT/DIT ratio was 1.16 ± 0.26 for the radioactive and 0.92 ± 0.30 for the stable compounds. Clinically evident hypothyroidism occurred only in patients with a very low iodine content and was not correlated with the proportion of iodothyronines found in the thyroid tissue. For instance, in two hypothyroid patients the iodothyronines corresponded to about 20 per cent of the iodocompounds of the tissue. These findings suggest that iodine depletion of the thyroid gland plays an important role in the development of clinical hypothyroidism in autoimmune thyroiditis and that up to a very late stage of the disease the thyroid is evidently capable of producing iodothyronines in fairly normal proportions.

Effect of changing intestinal bacterial flora on thyroid function in the rat.

Experiments were designed to determine if changes in rat intestinal bacterial flora are accompanied by changes in thyroid function. Attempts to modify intestinal bacterial flora of Sprague-Dawley (SD) rats were made by (a) feeding the non-orally absorbed antibiotic, kanamycin; (b) insanitary caging. Thyroid function was also compared in germfree and ex-germ-free animals. Qualitative and quantitative studies of intestinal bacteria were carried out concurrently; at the end of each study thyroidal radioactive iodine (RAI) uptakes and plasma radioactivities were determined at three or 24 hours after radioiodine (Na131I) was administered. Thyroid glands were weighed and total iodine concentration was measured as well as plasma protein-bound iodine (PBI). Kanamycin lowered the total aerobic and anaerobic bacterial counts of female rats and this was accompanied by reduced three hours thyroidal RAI uptakes after 42 and 72 days of treatment Insanitary caging for four or eight weeks did not change intestinal bacterial flora and there were no differences in thyroid function. Female germ-free animals had significantly smaller thyroids than conventional female rats. These studies have shown that reduction in the intestinal bacterial flora may affect thyroid function - simulating modest supplementation with iodine.

Determination of total iodine and iodate in sea water and in various evaporites

Iodine in sea water and evaporites is determined spectrophotometrically as the starch-iodine complex without prior separation or concentration of the iodine. In slightly alkaline solution, iodide is first oxidized to iodate with permanganate. Oxidized states of manganese are destroyed with iron(II) in phosphate medium without affecting the iodate. After acidification, iodide is added to react with the iodate in the presence of starch. The iodate content is determined by the same procedure, but without the addition of permanganate. As little as 0.1μg of iodine is determinable in the presence of 500 mg of chloride and 5 mg of bromide. The total iodine concentration in seven samples of sea water was found to vary from 50 ±3 to 84 ±6 μg l -1 with 50–100% present as the iodate.

Iodinated particles in the rat thyroid. I. A rapid separation method.

ABSTRACT In a first step, the quantitative preparation of the whole population of iodinated particles was reinvestigated in thyroids obtained from rats maintained in an isotopic equilibrium with 125I. The maximum yield in the iodinated particles was obtained for a 0.15 m sucrose solution in 0.1 m Tris-HCl buffer pH 7. This yield was 3.5 % and 1.7 % of the total iodine content of the thyroid for rats adapted to receive 50 (group 50) and 5 μg (group 5) of iodine daily respectively. The iodinated particles of group 50 were found to be more sensitive to pH variations than those of group 5. In a second step, a rapid method was developed to separate the whole population of iodinated particles into physiological populations (tentatively colloid droplets and secondary lysosomes). By centrifuging onto a discontinuous Ficoll gradient, three distinct iodine peaks were regularly obtained for rats of group 5 and 50 and also for other rats receiving a diet rich in iodine. For group 50, the iodine pools (127I) as measured by isotopic equilibrium were found to represent about 16% (peak 1), 25 % (peak 2) and 59 % (peak 3) of the total particulate iodine content of the gland. The possible nature of these three populations of iodinated particles is discussed.

Gaseous Iodine Measurements and Their Relationship to Particulate Lead in a Polluted Atmosphere

Abstract Gaseous iodine and particulate iodine and lead samples were collected simultaneously in a polluted atmosphere using activated charcoal and membrane filters. Concentrations of gaseous iodine varied from 10–18 ng m−3 and particulate iodine from 2–15 ng m−3 as determined by neutron activation analysis. The total iodine concentration found in this work is approximately twice that found in the unpolluted marine atmosphere. Lead concentrations varied from 0.4–3.7 µg m−3 as determined by atomic absorption spectrophotometry. There is an apparent relationship between the concentration of total particulate matter in the air and the ratio of particulate iodine to gaseous iodine. This relationship is consistent with laboratory investigations of gaseous I2 adsorption onto combustion aerosols reported by other investigators. Calculations indicate that the concentrations of gaseous iodine measured in this work should be sufficient to activate all lead containing particles to ice nuclei in a polluted atmosphere....

Improvements in intravenous cholangiography.

Infusion techniques are an important advance in intravenous cholangiography, and I was therefore most interested to read the article by Drs. Nolan and Gibson in your September issue. I fear, however, that this paper may encourage the unnecessary and possibly harmful escalation of Biligrafin dosage. Some patients apparently received 90 ml. of Biligrafin Forte. This dose contains 45 g of the methylglucamine salt of Biligrafin with a total iodine content of 22·5 g. For comparison one might consider the oral preparation of Telepaque. A double dose (6 g) of this substance, which might be required for a very large patient, contains only 4g of iodine.

Photometrische Titration der Särkepolysaccharide mit Jod. II. Mitt. Hydrolyse mechano‐chemisch abgebauter Amylose durch β‐Amylase

AbstractPhotometric Titration of Starch Polysaccharides by Iodine. Part 2: Hydrolysis of Mechano Chemically Degraded Amylose by β‐Amylase. With photometric titration of amylose by means of iodine, the course of the graph depends on molecular weight distribution, average molecular size and concentration of polysaccharides. Respective data are: size of the linear part of the titration graph, total iodine concentration at half saturation of amylose by iodine, and maximum value of extinction. This new method is applied to examine β‐amylolysis of natural amylose of various molecular size. High‐molecular substrates are degraded according to a single‐chain mechanism and amyloses having been swing‐milled for more than 48 h are degraded by a multichain mechanism. The change in the effect of β‐amylase occurs in the range between Pn 130 and 200, This change is to be contributed to differences in the molecular configuration of the substrate.

Potency of United States Pharmacopeia dessicated thyroid tablets as determined by the antigoitrogenic assay in rats.

ABSTRACT Ten samples of USP desiccated thyroid, 2 from an investigator and 8 purchased on the open market across the nation, were tested for metabolic potency by the antigoitrogenic bioassay technique and for total iodine by the USP assay technique. Four of the 10 samples were found to be markedly off potency. Although all the tablets were found to conform to the specifications of the Pharmacopeia of the United States of America for the total iodine content, 4 were found to be so variable in potency that they were essentially useless or even potentially dangerous, if used according to their labeled potency. A small sampling such as reported, demonstrating a relatively high percentage of USP desiccated thyroid tablets to be of questionably standardized biological activity, suggests that thyroid substitution medication of variable potency may represent a common and widespread pharmaceutical problem in the United States.

Butanol-Extractable Iodine in Human and Bovine Colostrum and Milk

Abstract High total iodine content and significant amounts of iodinated amino acids, but not of thyronines, have been reported in milk of various species. Since the human neonate requires thyroxine-like iodine compounds for central nervous system development, analyses of thyroxine-like iodine compounds such as butanol-extractable iodine of colostrum or early milk were indicated. Four samples of human milk 2-5 days post-delivery and 11 samples of bovine milk were examined for butanol-extractable iodine content. Thyroxine-like iodine compounds of colostrum or milk soon after parturition were extremely low, but total iodine values of milk supply abundant inorganic iodine for the mature neonatal thyroid.

ESTIMATION OF THYROID IODINE CONTENT BY THE OCCUPANCY PRINCIPLE

The " occupancy principle " states that in a rheostatic (constant-flow) system the ratio of occupancy to capacity is the same for all parts of the system. In a worked example, in which the total iodine content of the thyroid (i.e., the capacity of the thyroid) is the unknown, a single dose of iodine-129 is used as a tracer. The areas under the activity-time curves for the thyroid and for 1 litre of plasma give the occupancies; plasma capacity is simply the protein-bound-iodine content of 1 litre of plasma. Equating the occupancy/capacity ratios for plasma and thyroid gives a value of 5·6 mg. for total thyroid iodine content. Iodine content can be estimated differently, by using the peak plasma activity and the thyroid activity at this time — in this example, the result was 5·5 mg.

Thyroid physiology in the developing monkey fetus ( Macaca mulatta)

A series of observations defining thyroid physiology in the developing monkey fetus ( Macaca mulatta) were summarized in this paper. Follicle formation and colloid synthesis were apparent in the gland by conception age 50 days. They underwent vigorous proliferation and were progressively subdivided by interposing vessels and connective tissue. The total iodine content showed a fiftyfold increase between conception age 75 and 150 days yet gland weights increased only tenfold. The moieties, monoiodotyrosine (MIT), diiodotyrosine (DIT) and thyroxine (T 4) were present in constant ratios. The 24-hour 131I uptake per milligram of thyroid tissue in fetuses was 8–12 times greater than in their mothers. The distribution of 131I among the various moieties was about the same in all fetal thyroid glands studied. The significant difference of T 4 131I values observed between fetal and infant thyroid glands suggest that much less T 4 is released from the gland in fetal life than after birth. BEI values in fetal glands were relatively low at the younger ages, however, they increased progressively and approached maternal values by conception age 150 days. By term maternal and fetal values are equal for this animal and man. However, when the data were expressed in term of the T 4 concentration (molar) per milligram of protein nitrogen, the situation changed. The T 4 (SA) values, observed through further elaborated studies in fetal thyroid glands coupled with data of placental and fetal tissue indicated clearly that the 131I-labeled T 4 detected was of maternal origin. The fetal serum T 4 values, observed from relatively long term maternal administration of large doses of 131I-labeled T 4, showed little or no change from normal even though maternal values had exceeded normal by three times. There was also no indication of increased placental T 4 transport to the fetus as a result of the high maternal T 4 values.

A study of the adsorption of iodine and acetic acid from aqueous solutions on characterized porous carbons

The iodine/iodide/water and acetic acid/water systems have been used to study adsorption by characterized activated polyvinylidene chloride carbons and an activated coconut charcoal. The adsorbents were characterized in terms of micropore volume and effective surface area as provided by the Dubinin theory of adsorption. It was found that iodine adsorption is not restricted to monolayer coverage and that filling of transitional porosity occurred. The correct isotherm must employ free iodine concentration and not total iodine concentration. The effect of iodide concentration upon extent of iodine adsorption can then be predicted. Radioactive iodine studies suggest that the adsorbed species is I 2 and not ionic species. Acetic acid adsorption cannot be used realistically to measure surface areas or internal pore volumes.

Iodine in mitochondria and nuclei

The total iodine content of liver mitochondria obtained from hypothyroid rats was about 20% of that mitochondria from normal rats. Injecting the hypothyroid rats with 5.2 mμg of L-T 4 gm and killing them 2 minutes later produced a liver mitochondrial iodine content that was 56% of normal. The iodine increment had a half-life of 10 minutes as measured by the iodine content of mitochondria from animals killed in 30 and 180 minutes. Skeletal muscle mitochondria and liver nuclei from hypothyroid rats contained 65% and 50% as much iodine, respectively, as those from normal rats, and injecting the animals with 5.2 mμg of L-T 4 gm up to 3 hours before sacrifice produced no significant changes, although the iodine in muscle mitochondria rose slightly. The number of nucleoli per liver nucleus in untreated hypothyroid animals was 65% of that in normal nuclei, and was not changed by thyroxine treatment over the 3-hour period studied. These results are consistent with those reported previously on functional changes in liver mitochondria from hypothyroid rats killed 3 hours after L-T 4 administration in vivo, well before the hormone affects nuclear RNA metabolism. About 75% of the iodine in normal liver mitochondria was butanol-extractable or -insoluble, and so represented thyroid hormone; injection of 5.2 μg of L-T 4 gm 2 minutes before sacrifice raised the total iodine, butanol-extractable iodine, and butanol-insoluble iodine 20-fold.

Estimation of thyroid iodine in vivo by activation analysis.

THE usefulness of activation analysis for the estimation in vivo of total body sodium, chlorine and calcium in the human subject has recently been demonstrated1. Because of the remarkable concentration of iodine in the thyroid gland, irradiation of this organ by thermal neutrons should make it possible to estimate the total iodine content. To study this possibility we have carried out experiments with sheep, where the thyroid iodine content is of the same order of magnitude as in man.

Analytical Studies of Iodine in Food Substances

Four species of edible brown marine algae were fractionated by trichloroacetic acid precipitation and subsequent chromatography; and the iodine content of each fraction was determined. Quantitative determination of iodide form iodine was made possible by elimination of interfereing substances in cell extract using a weakly basic anion exchange resin column without drastic procedure.Although the iodine content of each algae was of much diversity owing to species, the iodide form iodine varied between 83~85% of total iodine independent on total iodine content. The rest of the iodine was mostly found in trichloroacetic acid precipitate probably in protein bound form; and each algae contained little trichloroacetic acid soluble non iodide form of iodine, probably a low molecular organic form iodine.

High specific activity labeling of protein with I-131 by the iodine monochloride method.

SummaryA modified iodine monochloride method suitable for preparing I131-labeled proteins of a high degree of radioactivity is described, and results are given. Hydrogen peroxide present in high level I131 preparations is destroyed with catalase. Then IC1 is added to a mixture of the I131 as iodide and the protein to be iodinated. Total iodine content of I131 preparations sets a limit on the specific activity of I131-labeled proteins that can be achieved with a low degree of iodination. In the two commonly used methods for producing I131 (fission of U235 and thermal neutron irradiation of natural tellurium) stable I127 and long-lived I129 are also formed. Analysis showed the total iodine content of fission product I131, as received from Oak Ridge National Laboratory soon after processing, to average 2.4 μg per 100 mc, 3 times the amount present as I131 (0.8 μg/100 mc). For I131 produced from tellurium it was substantially greater. Since the ratio of total iodine to I131 increases with time after processin...

Relationship Between thein VitroUptake of131I-triiodothyronine by Erythrocytes and Its Binding by Serum Proteins in Thyroid Disease1

The in vitro uptake of 161I-triiodothyronine (T3) by red blood cells (RBC) and its binding to serum proteins were estimated in 400 subjects (180 normal, 114 thyrotoxic and 106 hypothyroid) chosen at random. Total thyroxine-binding globulin (TBG) capacity and protein-bound iodine concentration (PBI) were also estimated in 89 subjects (31 normal, 35 thyrotoxic and 23 hypothyroid). The binding of T3 to serum proteins was shown to be more accurate (95.8%) than its uptake by RBC (89.8%) in the study of thyroid function, and both methods were more reliable in diagnosing hypothyroidism (95.3 and 89.6%) than thyrotoxicosis (92.1 and 82.4%). The uptake of T3 by RBC increases and the binding of T3 to serum proteins decreases as the concentration of thyroxine (T4) in plasma is artificially raised. The values for the uptake of T3 by RBC and its binding to serum proteins were demonstrated to be dependent on free TBG capacity. The maximum uptake of T3 by RBC and the lowest value for the binding of T3 by serum proteins ...

Particulate iodoprotein in abnormal thyroid glands.

The distribution of stable iodine has been measured in 14 abnormal human thyroid glands, and the distribution of radioiodine has been measured in 6 of these. More than 10% of the stable iodine of 12 specimens from 8 patients was associated with the “nuclear” centrifugal fraction, and this fraction accounted for nearly half the stable iodine and radioiodine of a diffusely hyperplastic congenital goiter with a high total iodine content. When measured, the specific activity of the radioiodine in these glands was usually less in the particulate centrifugal fractions than in the soluble fraction. The iodine of the “nuclear” fraction could be solubilized partially by urea and thioglycolate, and by 15-min exposure to trypsin. The solubilized iodoprotein moved near thyroglobulin by starch gel electrophoresis, differed from thyroglobulin in salting-out characteristics, and contained MIT and DIT but no detectable iodothyronine.