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Showing papers on "Iodine published in 1976"


Journal ArticleDOI
TL;DR: Smoking statistically increased the amount of thiocyanate and decreased that of iodine in the saliva samples significantly and male smokers had significantly more thiockinate and less ionizable iodine in saliva than female smokers.
Abstract: The concentration of thiocyanate and ionizable iodine was determined with saliva samples from two test groups, smokers (N = 27) and nonsmokers (N = 92). The contents of both ions were also compared as to sex and the amount of cigarettes smoked. The concentrations of the ions studied were dependent on each other-the less iodine, the more thiocyanate in the samples. Females had significantly more iodine and less thiocyanate concentrations than males. Smoking had an increasing effect on the concentration of thiocyanate and a decreasing effect on the content of ionizable iodine in the saliva of the volunteers. The lower amount of iodine ions in the saliva of smokers may restrict the nonthyroidal metabolism of the thyroid hormone in humans.

91 citations


Journal ArticleDOI
TL;DR: Twenty‐four of twenty‐eight patients with erythema nodosum and sixteen of seventeen patients with nodular vasculitis responded to treatment with potassium iodide and an immunosuppressive effect mediated by heparin is suggested.
Abstract: Twenty-four of twenty-eight patients with erythema nodosum and sixteen of seventeen patients with nodular vasculitis responded to treatment with potassium iodide. Relief of symptoms occurred within 2 days. The average duration of treatment was 3 weeks and the lesions took an average of 2 weeks to resolve. The possible mode of action of potassium iodide is discussed and an immunosuppressive effect mediated by heparin is suggested.

91 citations


Journal ArticleDOI
TL;DR: The data support the concept of an as yet unknown organic form of iodine that limits thyroid adenylate cyclase responsiveness to TSH stimulation, and direct measurement of newly formed organic iodine in vitro demonstrated it to be inversely proportional to the final cAMP concentration achieved by T SH stimulation.
Abstract: Rats maintained on a low-iodine diet were hypophysectomized, and their diet was then enriched with iodide. Cyclic AMP(cAMP) concentrations achieved in their thyroids following in vitro TSH stimulation were significantly lower than those in the thyroids of control animals that did not receive dietary iodide enrichment. The addition of 0.1% methimazole (MMI) or 1% KClO4, to the diet abolished this inhibitor effect of iodide. The administration of triiodothyronine in the diet did not reproduce the inhibitor effect of iodide. The effect of iodide in vitro on the thyroid cAMP response to TSH was then investigated using paired thyroid lobes obtained from intact rats fed a lowiodine diet. During a 15-min incubation period, concentrations of iodide up to 10−3M, together with TSH (125 mU/ml), did not affect the thyroid cAMP response to TSH. In contrast, the preincubation of the lobes in 5 × 10−5M Nal for 2 h preceding a final 15-min incubation in medium containing TSH alone resulted in final cAMP concentrations si...

58 citations


BookDOI
01 Jan 1976

58 citations


Journal ArticleDOI
TL;DR: In pre-weaning rats, after a single injection of both [131I]L-T4 and [125I]Na, extrathyroidal radioactivity disappeared more slowly than in 30 days old rats and adult animals, which suggests that iodide concentrations of extr Kathyroidal tissues are higher before than after weaning.
Abstract: The thyroid function in development was investigated in post-natal rats. The thyroid iodine content rapidly increased from birth (137 +/- 26 ng iodine/mg thyroid) up to day 10 (338 +/- 42 ng iodine/mg thyroid) then increased more slowly up to day 30 (425 +/- 34 ng iodine/mg thyroid). The maximal plasma concentration of thyroxine was observed on day 16 (56.9 +/- 3.5 ng T4/ml) and of iodide on day 10 (110.2 +/- 12.6 ng I-/ml). The turnover rate constant of extrathyroidal thyroxine was higher at birth (8.0 +/- 2.3 %/h) than at any older age studied (average 6 %/h). Thyroxine secretion by the thyroid was more intense before weaning (37 ng hormonal iodine/h/100 g body weight on days 10 and 20) than after weaning (22 +/- 6 ng hormonal iodine/h/100 g body weight in 30 days old rats). The peripheral deiodination rate of thyroxine represented about 90 % thyroxine secretion rate in newborn and 10 days old rats and only 40% in adult females. In pre-weaning rats, after a single injection of both [131I]L-T4 and [125I]Na, extrathyroidal radioactivity disappeared more slowly than in 30 days old rats and adult animals. This suggests that iodide concentrations of extrathyroidal tissues are higher before than after weaning.

50 citations


Journal ArticleDOI
TL;DR: The results suggest that iodine deficiency alone is sufficient to explain the effects of the Remington low-iodine diet and that it is not necessary to postulate the presence of a goitrogen.
Abstract: Large variations are frequently encountered in the thyroidal responses of rats to commercially available low-iodine diets. The major aim of this investigation was to attempt to correlate these variations with differences in the iodine content of the diets. A method was developed for measuring the iodine content of low-iodine diets which was sufficiently sensitive to discriminate between a diet containing 15–20 ng of iodine per g and one containing 30–40 ng of iodine per g. Large differences were observed between various commercial low-iodine diets in their ability to induce goiter and to affect other indices of thyroid function, and these differences could be correlated with differences in the iodine content. The most severe iodine deficiency occurred in rats that were fed a Remington diet containing 15–20 ng of iodine per g. After 3 months on this diet, thyroid weight increased about 7-fold, thyroid 127I concentration was reduced to about 0.5% of control values, serum thyroxine (T4) was reduced to <0.25 ...

47 citations


Journal ArticleDOI
TL;DR: It appeared that the enzyme catalyzes thyroid hormone synthesis at a slower rate than iodination, a substrate of the iodination reaction, may also have other effects on the activity of thyroid peroxidase.
Abstract: The kinetics of tyrosine iodination and of thyroxine synthesis in thyroglobulin, different reactions catalyzed by the sane enzyme (thyroid peroxidase), have been compared. Thyroxine synthesis always began after a lag period of 3–5 min. This lag was constant whatever the rate of iodination; this rate of iodination was increased either by increasing the concentration of iodide or enzyme or by decreasing the concentration of thyroglobulin. Increasing the rate of iodination resulted in increasing the number of iodine atoms incorporated during the lag period. Thus the lag observed for thyroxine synthesis was constant and did not depend on the fact that free iodide or non-iodinated tyrosine residues of thyroglobulin were exhausted before thyroxine synthesis occurred. Finally, it appeared that, whatever the explanation of the lag, the enzyme catalyzes thyroid hormone synthesis at a slower rate than iodination. The existence of a lag also allowed us to prepare thyroglobulin samples with different iodine contents but without thyroid hormones. Thus iodination and thyroxine synthesis could be studied independently and the following results were obtained. 1 Iodotyrosine residues which can couple to form thyroxine are made considerably before coupling occurs. 2 H2O2 is required for coupling of these hormonogenic residues; thus the coupling reaction requires enzymic oxidation of the iodotyrosine residues. 3 In addition a strict requirement for iodide was needed for coupling: the requirement was dependent on the concentration of iodide. Thus iodide, a substrate of the iodination reaction, may also have other effects on the activity of thyroid peroxidase.

47 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that a catalytic amount of iodine or hydrogen iodide (i.e., aq. HI-solution) can be used in the presence of dimethyl sulfoxide to afford the corresponding disulfides nearly quantitatively.
Abstract: Mercaptans were oxidized readily by a catalytic amount of iodine or hydrogen iodide (i.e., aq. HI-solution) in the presence of dimethyl sulfoxide to afford the corresponding disulfides nearly quantitatively.

46 citations


Journal ArticleDOI
TL;DR: A study of the sorption of iodate and iodide from solution (40 μg 1 −1 - I) onto fourteen natural river sediments, peat and twelve sediment components showed that in rivers where the suspended sediment load is less than 0.1 gl − 1 significant sorption (> 0.5 μ g 1 − 1 ) of iodide is unlikely to occur as discussed by the authors.

45 citations


Journal ArticleDOI
01 Apr 1976-Diabetes
TL;DR: The shelf life of iodinated insulin appears to be related better to the average iodine content than to any other factor, presumably because of decay catastrophe.
Abstract: 125 I-insulins, prepared by iodination with chloramine T in marked excess or by stepwise, stoichiometric addition of the oxidizing agent, were compared with respect both to their molecular distribution of iodine and to their suitability for use in a cultured lymphocyte receptor assay. Iodination of insulin in aqueous solution results in the same distribution of iodine atoms, independent of experimental method and dependent only on the average iodine number. This distribution can be calculated on the basis of a Monte Carlo simulation, For insulin iodinated at an average of 0.8 I atoms per molecule, approximately 50 per cent of the radioactivity is in other than monoiodoninsulin. Purification methods that separate on the basis of charge, such as starch-gel electrophoresis, are then required, to obtain monoiodoinsulin. More highly iodinated insulin do bind to the lymphocyte receptor, although, as in radioimmunoassay, the overiodinated species are less satisfactory for use as tracers. The shelf life of iodinated insulin appears to be related better to the average iodine content than to any other factor, presumably because of decay catastrophe. There is no evidence to suggest that exposure to chloramine T in marked excess for a few seconds is deleterious to insulin.

36 citations


Journal ArticleDOI
TL;DR: Iodophors tested in this study demonstrated a distinct superiority to noncomplexed iodine solutions (tincture and aqueous iodine solutions) as wound and skin cleansers.
Abstract: Iodophors are effective germicidal agents that have prolonged antiseptic activity in contaminated wounds. A nontoxic surfactant, Pluronic F-68, has been used to formulate a safe and effective iodophor. The parameters necessary to regulate the activity of the iodophor were studied to develop a potent, yet safe bactericidal solution for use in human subjects. The parameters found to be most important were the pH of the solution and the concentration of sodium iodide. Lowering the pH of iodophors increased their stability and antiseptic activity. The free iodine in iodophor solutions prepared with a low pH is predominantly the highly biocidal diatomic iodine (I2). The concentration of iodide regulated the equilbrium of the dissolved iodine between its free and complexed form. Increasing the concentration of iodide in the iodophor lowered the amount of free iodine in solution and enhanced the concentration of the complexed iodide. It is the level of free iodine in an iodophor that determines its antiseptic activity. Low levels of free iodine yielded iodophors that had a slow bacterial kill rate but a prolonged duration of action. Manipulation of these variables permitted the generation of iodophors that varied considerably in their kill rates of bacteria and their duration of antibacterial activity. Iodophors tested in this study demonstrated a distinct superiority to noncomplexed iodine solutions (tincture and aqueous iodine solutions) as wound and skin cleansers.

Journal ArticleDOI
TL;DR: In this paper, it was shown that gamma irradiation can release iodine in small amounts from powdered samples of cesium iodide and barium ionide, but not from zirconium iodides, and the amount of iodine released was measured using silver foil detectors in sealed capsules that contained the salt.
Abstract: Gamma irradiation was found to release iodine in small amounts from powdered samples of cesium iodide and barium iodide, but not from zirconium iodides. The amount of iodine released was measured using silver foil detectors in sealed capsules that contained the salt. The amount of release was markedly affected by impurities, especially water, that were difficult to control; therefore, G values calculated were inaccurate but of the order of 10/sup -3/ atoms of iodine released for 100 eV of energy absorbed for CsI and BaI/sub 2/ near room temperature. The G values for the zirconium iodides were much smaller. The phenomenon of release of iodine from the ionic iodides by gamma radiation is discussed on the basis of published theories of the formation of defects in solids.

Journal ArticleDOI
TL;DR: In this article, the reproducibility of the iodide-selective electrode was shown to be 2.3% for 10-5N solutions, and the limits of determination were 33 ng NaAsO2, 32 ng Na2SO3, 44 ng C6H8O6, 13 ng N2H4·2 HCl and 17 ng NH2OH·HCl per ml.

Journal ArticleDOI
TL;DR: Throughout embryonic development, iodine was bound more and more to TG molecules, which were resistant to dissociation with SDS, and the low efficiency of the TG of the chick embryo as a thyroidal hormone-forming protein was compensated for by its high degree of iodination.
Abstract: Stable iodine was measured in the thyroid gland of the chick embryo from day 9 to day 20 of incubation in order to evaluate quantitatively the functional development of the gland. Total iodine content increased progressively during incubation. From day 9 to day 17 of incubation, this increase resulted from the increases of pellet-bound iodine and of soluble iodine. Afterwards, it essentially paralleled the increase of the soluble thyroglobulinbound iodine which reflected the increase in both thyroglobulin content and the degree of iodination of the thyroglobulin. The total iodine, thyroglobulinbound iodine and thyroglobulin (TG) content, increased as power functions of time during incubation, with critical times on days 11 and 15. Their concentrations also increased during the whole incubation period, while the iodide concentration remained roughly constant (25 ng/mg) from day 13 to day 19. Only one iodoprotein, 19.5 S TG, was found, and its heterogeneity of iodination was demonstrated during the whole pe...

Journal ArticleDOI
TL;DR: Almost non-iodinated human goiter thyroglobulin has been iodinated in vitro by thyroid peroxidase to levels as high as 75 iodine atoms per mol of protein, suggesting that the tyrosines which are coupled with a high efficiency are iodinated sequentially.
Abstract: Almost non-iodinated human goiter thyroglobulin has been iodinated in vitro by thyroid peroxidase to levels as high as 75 iodine atoms per mol of protein. The following results were obtained. 1 The iodine distribution obtained in vitro with human thyroglobulin strongly ressembles that obtained in vitro for rat thyroglobulin. Thus the distribution of iodine seems to depend essentially on the structure of thyroglobulin and on the reactivity of the different tyrosine residues. 2 Although the number of hormone residues increased with iodination the highest efficiency of hormone synthesis was obtained in a very narrow range of iodination: in vitro (40%) between 25 and 30 iodine atoms, and in vitro (48%) between 10 and 20 atoms. This result suggests that the tyrosines which are coupled with a high efficiency are iodinated sequentially. 3 Maximal thyroxine content was found to be lower than ∼ 3 mol/mol of thyroglobulin. This result might mean that the two 12-S subunits of thyroglobulin are not identical and that one of them is able to produce 2 mol of hormone while the second only 1 mol.

Journal ArticleDOI
TL;DR: It is suggested that one of the inhibitory actions of excess iodide is on the adenylate cyclase-cyclic AMP system and further, that iodide can elicit its inhibitory action after its conversion to some form of organic iodine.
Abstract: In a previous paper, we demonstrated that an inhibitory action of excess iodide on thyrotropin- induced thyroid hormone secretion occurs at a site subsequent to the generation of cyclic AMP. In the present study, however, we have found that thyroidal cyclic AMP formation induced by thyrotropin in vitro was markedly inhibited by the acute administration of excess iodide to mice fed a low iodine diet. In contrast, excess iodide failed to produce inhibition in animals fed a regular diet. In oitro stimulation by long-acting thyroid stimulator (LATS), prostaglandin E2, and 4-methylhistamine of cyclic AMP formation in mouse thyroid lobes was also significantly inhibited by the acute in vivo administration of excess iodide. The inhibition was completely relieved by the administration of methimazole prior to excess iodide. Furthermore, it has been shown that thyroid adenylate cyclase activity induced by thyrotropin was markedly depressed by excess iodide under similar experimental conditions. Therefore, it is sug...

Journal ArticleDOI
TL;DR: The Committee on Drugs of the American Academy of Pediatrics has reviewed the use of iodides in the therapy of asthma and other chronic pulmonary diseases and recommended dosages are many times greater than the average human thyroid gland delivers to the circulation per day.
Abstract: Neonatal deaths from tracheal obstruction caused by congenital goiters have been reported from such widely scattered locales as Buffalo, New York, New York City, Philadelphia, Washington, D.C., Seattle, Tokyo, Japan, and Glasgow, Scotland. The mothers of these infants had asthma and were receiving conventional doses of iodides, either as potassium iodide or as mixtures of bronchodilators and iodides. Because of these deaths, the Committee on Drugs of the American Academy of Pediatrics has reviewed the use of iodides in the therapy of asthma and other chronic pulmonary diseases. Five current textbooks advocate the use of iodides in chronic asthma. 1-5 "Iodide compounds have a stimulating effect on bronchial secretions and represent expectorants of major importance in treating asthma and particularly status asthmaticus." 2 The AMA Drug Evaluations 6 recommends the use of iodides only for short-term medication. Current Pediatric Therapy 7 emphasizes careful patient selection because only an occasional patient may benefit. Dosage recommendations usually are 300 mg of potassium iodide every two hours in adults 1 and 60 mg per year of age four times daily in children. 4 These dosage recommendations are many times greater than the 65 mg of organic iodine (T4 and T3) which the average human thyroid gland delivers to the circulation per day, or the estimated daily adult iodide requirement of 200 mg of iodide. 8 As a matter of fact, these recommended dosages for iodides represent 10 to 30 times the total body content of iodide! Many preparations–some of which are available on an over-the-counter (nonprescription) basis–contain iodides, including antiasthmatic preparations, expectorants, and preparations whose trade names may not suggest the presence of iodides.

Journal ArticleDOI
TL;DR: Uptake of 125‐iodide by normal mammary tissue and skeletal muscle was similar in all groups of tumor‐bearing mice, and was not influenced by the presence of an excess of non‐radioactive iodide or of perchlorate.
Abstract: Mammary adenocarcinoma were induced in ovariectomized females inbred GR/Afib mice by treatment with progesterone and estrone (P + O). For maintenance the tumors had been transplanted sc into castrated male mice of the same strain. The study included 2 hormone-responsive (HR) lines and 3 hormone-independent (HI) lines. Approximately 14 pg of I were injected ip (between .15-.23 Ci 125-iodide). 3 hours postinjection the mice were killed. Blood thigh muscles normal mammary glands mammary tumors and a section of trachea with the thyroid gland were removed. The content of 125-iodide was determined in a Selectronic gamma counter. At this time 15% of the isotope injected was found in the blood and 3% in the thyroid gland. The HR tumors accumulated about 14% of the iodide injected. The HR tumors took up 21 times more 125-iodide than the HI tumors not treated with P + O and 5-10 times more than tumors in mice treated with P + O. The uptake of 125-iodide in the 2 HI tumor lines treated with hormones differed significantly from each other and from the tumors not treated with P + O (p less than .01). The uptake of 125-iodide by skeletal muscle and normal mammary tissue was low in all mice. As increasing amounts of nonradioactive carrier iodide were added to the tracer dose of 125-iodide injected into the mice bearing HR tumors a decrease in uptake of 125-iodide to about 1/7 of controls were observed but not in HI tumors not receiving P + O treatment. HI tumors treated with P + O showed a slight reduction of 125-iodide uptake. The amount of radioactive iodide in the blood remained the same. Thyroid gland uptake of 125-iodide was reduced to about 1/25 of controls by the presence of nonradioactive iodide. Skeletal muscle and normal mammary tissue uptake were unaffected by excess of nonradioactive iodide. When 10 mg of perchlorate were injected simultaneously with the 125-iodide into HR tumor-bearing mice the mammary tumor uptake was reduced to about 1/7 and the uptake of 125-iodide by the thyroid tissue was reduced to about 1/80. In another experiment the normal lactating mammary gland was shown to be capable of concentrating iodine from the blood. HR mouse mammary tumors were shown to concentrate iodide but HI mammary tumors did not. Since the uptake of iodide by HR tumors was about 20 times that of HI tumors this determination may be of value in establishing hormone dependency in a given tumor. However HR tumors in time have usually progressed to become HI tumors. This has been attributed to the presence of 2 kinds of tumor cells. A consistent correlation of hormone dependency and increased iodide uptake by mammary tumors in humans has not yet been shown but if present it may prove to be a valuable method of determining hormone-dependent breast cancer.

Journal ArticleDOI
TL;DR: The comparison of relative T3' and T4 formation in enzymatically iodinated thyroglobulin with corresponding values reported for the intermolecular (DIHPPA) model for T 4 formation, indicates that the peroxidase model system simulates much more closely the relative formation of T4 seen in vivo.
Abstract: It was observed in the present investigation that labeled thyroxine (T4) comprised less than 2% of the total 131I in the thyroids of severely iodine-deficient rats labeled with 131I for 18-24 h, a much lower value than had previously been reported for iodine-deficient rats. This low value was attributable to two factors: 1) the use of a diet low enough in iodine content to produce extreme iodine deficiency, and 2) the use of a paper chromatography system that successfully separates T4 from the minor iodothyronines, 3,3'-diiodothyronine (T2) and 3',5',3-triiodothyronine (reverse T3; T3'). Formation of the minor iodothyronines, while low, becomes appreciable in relation to T4 formation in severe iodine deficiency. In the present study, the formation of labeled T2 was significant only in iodine deficiency, and the highest values were observed in the most severely iodine-deficient rats. In the latter, labeled monoiodotyrosine (MIT) comprised approximately 60% of the total 131I in the thyroid, and the increased formation of T2 could be attributed to the increased probability of coupling between two molecules of MIT. The formation of labeled T3', on the other hand, was significant in thyroids from both iodine-deficient and iodine-sufficient rats. Similarly, in thyroglobulin iodinated in vitro with thyroid peroxidase to varying levels of iodination, the formation of T2 was evident only at lower levels of iodination, whereas the formation of T3' was significant at all levels of iodination. The comparison of relative T3' and T4 formation in enzymatically iodinated thyroglobulin with corresponding values reported for the intermolecular (DIHPPA) model for T4 formation, indicates that the peroxidase model system simulates much more closely the relative formation of T3' and T4 seen in vivo.

Journal ArticleDOI
01 Jan 1976-Analyst
TL;DR: A method for the determination of trace amounts of iodine in dry plant material using alkaline fusion of the sample in the presence of an iodine carrier, followed by isolation of iodine by a solvent extraction and a precipitation step is described.
Abstract: A method for the determination of trace amounts of iodine in dry plant material is described. The method is based on the radiochemical separation of iodine-128 using alkaline fusion of the sample in the presence of an iodine carrier, followed by isolation of iodine by a solvent extraction and a precipitation step. The precision of the method is about 5% at the 0.05 p.p.m. level and 10% at the 0.005 p.p.m. level of iodine. Results for two international reference plant materials are reported.

Journal ArticleDOI
TL;DR: Values of the 1291/1271 ratio in deer appear to vary inversely with the iodine concentration of the thyroid, and near saturation levels of mineral iodine in commercial feeds and salt licks may account for differences in the lZ9I levels of cows and deer.
Abstract: A combination of neutron activation and mass spectrometry has been used to determine the concentrations of fissiogenic 1291 and stable lZ7I in thyroids of grazing animals and in mineral iodine. The 1291/1z71 ratios are lowest in mineral iodine and in a given area lower in cow thyroids than in deer thyroids. Near saturation levels of mineral iodine in commercial feeds and salt licks may account for differences in the lZ9I levels of cows and deer. Values of the 1291/1271 ratio in deer appear to vary inversely with the iodine concentration of the thyroid.

Journal ArticleDOI
TL;DR: In this article, the electrochemical behavior of iodide and iodide in AlCl3+NaCl mixtures with compositions ranging from NaCl saturated melts to AlCl 3 + NaCl (63+37 mol %) at platinum and tungsten electrodes was studied.

Journal ArticleDOI
TL;DR: This paper describes an in vivo method for measurign total thyroidal iodine stores by activation analysis, its evaluation and measurements in thyrotoxic patients, which showed low levels in untreted and treated patients and a marked increase in patients studied whilst in clinical remission.
Abstract: This paper describes an in vivo method for measurign total thyroidal iodine stores by activation analysis, its evaluation and measurements in thyrotoxic patients. There was good correlation between measurements of solutions of iodine and post-mortem thyroids by activation analysis and chemical analysis. Measurements in thyrotoxic patients showed low levels in untreted and treated (antithyroid drugs) patients and a marked increase in patients studied whilst in clinical remission. The practical importance of this method of measurement of thyroidal iodine stores is that it is a relaible in vivo measurement obtained at a single visit and should enable the definition of the relationship of thyroidal iodine stores to pathophysiology and prognosis.

Journal ArticleDOI
TL;DR: A clear discrepancy was shown between the euthyroid state of this patient and the total lack of iodinating activity of the isolated peroxidase, indicating a complete iodine organification defect.
Abstract: Two patients (G2, G3) with iodine organification defect were studied. The first patient (G2), a 25-year-old women with no clinical hypothyroidism, had had her goiter for 10 years; 62% of the thyroidal iodine was released by perchlorate indicating iodine organification defect. The thyroid tissue obtained at thyroidectomy contained a normal 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 (G2-TPO) behaved on DEAE cellulose chromatography very differently from those of hog (P-TPO) or another human goiter peroxidase (G1-TPO) (Pommier, et al., J Clin Endocrinol Metab 39: 69, 1974): the molarity of elution was 2M NaCl instead of 0.15 mM. 2. Both P-TPO and G2-TPO catalyzed iodide peroxidation (I- leads to I2) but the Km (iodide) value for G2-TPO was much lower (2.3 x 10(-2) M) when compared with that of P-TPO (3.7 x 10(-3) M) or G1-TPO (3.5 x 10(-3) M). In addition, the optimum pH for this reaction differed markedly (pH 6.1 instead of 7.9). 3. G2-TPO was poorly efficient in catalyzing the oxidation of gaiacol to tetragaiacol. 4. G2-TPO was unable to perform the iodination of non-iodinated goiter thyroglobulin whatever the pH and the iodide concentration. 5. Thyroglobulin from this goiter (G2) was almost not iodinated (0.0014%), i.e., 0.07 atoms iodine/mole thyroglobulin), and its total content in the gland was very low (0.3-4 g/1000 g wet tissue instead of 25 g). A clear discrepancy was thus shown between the euthyroid state of this patient and the total lack of iodinating activity of the isolated peroxidase. The second patient (G3), a 17-year-old man with clinical hypothyroidism, had had his goiter for 5 years. 100% of the thyroidal iodine was released by perchlorate indicating a complete iodine organification defect. The thyroid tissue obtained at thyroidectomy contained no peroxidase activity when tested before and after treatment of the particulate material by trypsin and digitonin and even in the presence of hematin. Thyroglobulin from this goiter, which was almost non-iodinated (0.0014%), was present in normal amounts in the gland (congruent to 25 g/1000 g).

Journal ArticleDOI
W. Fuss, K. Hohla1
TL;DR: In this article, it was shown that the energy decrease resulting from repeated shots with the same gas filling of an iodine laser is solely due to the accumulation of I 2 and the consumption of iodide.



Journal ArticleDOI
01 Jul 1976-Talanta
TL;DR: Thiocyanate and thiosulphate ions are oxidized by iodine in alkaline media to sulphate ions, which results in the ultimate production of 19 and 24 iodine molecules, respectively.

Journal ArticleDOI
TL;DR: In this paper, the fraction of iodine atoms produced in the electronically excited 2P1/2 state by broadband flash photolysis of methyl iodide was determined by monitoring the gain of an iodine laser amplifier as a function of time.
Abstract: We have determined the fraction of iodine atoms produced in the electronically excited 2P1/2 state by broadband flash photolysis of methyl iodide. Rate constants for the deactivation of electronically excited iodine by methyl iodide and by methyl radicals have also been evaluated. In addition, an upper limit for the rate constant for the reaction of electronically excited iodine with methyl iodide to produce molecular iodine and methyl radicals has been determined. These measurements have been made by monitoring the gain of an iodine laser amplifier as a function of time.