Showing papers on "Iodine published in 1993"

Two Simple Methods for Measuring Iodine in Urine

Abstract: Urinary iodine excretion is currently the most convenient laboratory marker of iodine deficiency Accelerating international interest in correcting this condition demands rapid, simple methods for

Hydrogen peroxide and lignification

Abstract: The production of hydrogen peroxide in plant tissue is demonstrated quickly with a simple histochemical test. The test solution, 50 mM potassium iodide in a 4% (w/v) potato starch suspension, is applied to the cut surface of the tissue to be tested. Hydrogen peroxide oxidizes iodide ions to iodine; the iodine is complexed by the starch to form a blue-purple color. This test detects hydrogen peroxide production in cells undergoing lignification, i.e. tracheary elements and phloem fibers, and in some epidermal cells. In addition there is a rapid production of hydrogen peroxide in crushed cells. The test is negative under (i) anaerobic conditions and (ii) in the presence of catalase.

Surface chemistry of colloidal silver: surface plasmon damping by chemisorbed iodide, hydrosulfide (SH-), and phenylthiolate

Abstract: The optical changes that occur upon the addition of iodide, iodine, and colloidal silver iodide to a colloidal solution of silver particles (6-nm mean diameter) were monitored spectrophotometrically. For small concentrations of added I - and I 2 (formation of less than a monolayer of adsorbate), the changes in the shape of the silver plasmon absorption band are practically identical. Silver iodide particles in contact with silver particles affect the plasmon band only slightly. It is concluded that the AgI molecules formed by the surface oxidation of the Ag particles by iodine do not possess the properties of bulk AgI

Amelioration of some pregnancy-associated variations in thyroid function by iodine supplementation.

Abstract: Knowledge of the effect of differences in iodine intake levels on public health in areas with no endemic goiter is limited. Groups at risk when iodine intake is relatively low are pregnant and lactating women and their newborns. A prospective randomized study was performed to evaluate the effect of iodine supplementation in an area where the median daily iodine excretion in urine is around 50 micrograms. Fifty-four normal pregnant women were randomized to be controls or to receive 200 micrograms iodine/day from weeks 17-18 of pregnancy until 12 months after delivery. In the control group, serum TSH, serum thyroglobulin (Tg), and thyroid size showed significant increases during pregnancy. These variations were ameliorated by iodine supplementation. Iodine did not induce significant variations in serum T4, T3, or free T4. Cord blood Tg was much lower when the mother had received iodine, whereas TSH, T4, T3, and free T4 levels were unaltered. The results suggest that a relatively low iodine intake during pre...

Screening for thyroid diseases in an iodine sufficient area with sensitive thyrotrophin assays, and serum thyroid autoantibody and urinary iodide determinations.

Abstract: Summary OBJECTIVE The present study was designed to investigate the prevalence of thyroid dysfunction and Its relation to thyroid autoantibodies and urine iodide concentration in apparently healthy people residing in Sapporo, a city of northern Japan, where the iodine intake is high. DESIGN AND SUBJECTS Serum TSH and thyroid autoantibodies, and urine iodide were measured in 4110 people (2931 men and 1179 women) (age 456 ± 103 years (mean ± SD)) who were recruited at the hospital for medical examinations. RESULTS The thyroid autoantibodies were positive in 6.4% of males and 13.8% of females with an age-related increase. Of the people with positive antibodies, 87.2% had normal TSH values (0.15–5.0 mU/l) as measured by a sensitive assay. The prevalence of unsuspected hyperthyroidism as defined by suppressed TSH values was 0.61%, of which 64% was diagnosed as Graves' disease based on positive thyrotrophin receptor antibody results. The prevalence of unsuspected hypothyroidism, as evidenced by supranormal TSH, was 0.68% for males and 3.13% for females with an age-related increase. Of those with hypothyroidism, 45.5% were autoantibody positive. The overall prevalence of Hashimoto's thyroiditis was 13.11% for females and 6.15% for males. The urine iodide levels of hypothyroidism with a positive autoantibody of 38.5 (17.7–83.9)μmol/l and a negative autoantibody of 34.9 (17.9–67.9) μmol/l were both significantly higher than that of normal subjects (26.9 (14.6–49.6) μmol/l) (P <0.01). When iodine intake was restricted for 6–8 weeks for hypothyroid subjects, the elevated TSH and thyroglobulin and low free T4 levels were reversed in the autoantibody negative but not in the positive group. CONCLUSIONS This study provides further information on the prevalence of thyroid dysfunction and autoimmune thyroid diseases in an iodine sufficient area. In addition, it suggests that more than half of the patients with unsuspected hypothyroidism were negative for autoantibodies and that the excessive iodine intake may be involved in causing latent hypothyroidism.

A furan fatty acid and indoxyl sulfate are the putative inhibitors of thyroxine hepatocyte transport in uremia

Abstract: We studied the effects of 3-carboxy-4-methyl-5-propyl-2-furan-propanoic acid (CMPF), indoxyl sulfate, and hippuric acid on iodide production by rat hepatocytes in primary cultures. We questioned whether these substances could explain the alteration of serum thyroid hormone parameters observed in renal failure. Iodide production from [125I]T4 by rat hepatocytes was significantly inhibited in the presence of serum from uremic patients. Serum concentrations of CMPF, indoxyl sulfate, and hippuric acid were markedly elevated in uremic patients. The minimum concentration that inhibited iodide production, when expressed as a molar ratio of the inhibitor to BSA, was 0.13 for CMPF, 0.53 for indoxyl sulfate, and 1.33 for hippuric acid. This molar ratio was lower than the corresponding mean molar ratio in uremic sera for CMPF (0.38) and indoxyl sulfate (0.63), while it was higher than that found for hippuric acid (0.85). The inhibition was reproduced when the inhibitors were added to normal human serum. The decreased iodide production was not due to the inhibition of deiodinase activity. The deiodination of rT3 by rat liver microsomes was unaffected by these inhibitors. Charcoal adsorption of uremic serum normalized the iodide production by hepatocytes. This normalization coincided with almost complete removal of CMPF and indoxyl sulfate, with a concomitant reduction of the free T4 fraction. Dialysis of uremic serum only partially restored iodide production. Even though indoxyl sulfate and hippuric acid were no longer detectable, a high concentration of CMPF remained in the serum. The serum free T4 fraction remained elevated in uremic patients after dialysis. Our studies indicate that CMPF and indoxyl sulfate in concentrations normally present in the serum of uremic patients inhibit cellular transport and subsequent deiodination of T4. These substances may account for the low total T3 level in uremic patients.

Iodine replacement in fibrocystic disease of the breast

Abstract: Objective To determine the response of patients with fibrocystic breast disease to iodine replacement therapy Design Review of three clinical studies beginning in 1975: an uncontrolled study with sodium iodide and protein-bound iodide; a prospective, control, crossover study from iodide to molecular iodine; and a prospective, control, double-blind study with molecular iodine Setting University affiliated breast-treatment clinics Patients Study 1: 233 volunteers received sodium iodide for 2 years and 588 received protein-bound iodide for 5 years Study 2: the treatment of 145 patients from study 1 treated with protein-bound iodide for several months who still had symptoms was switched to molecular iodine 008 mg/kg; 108 volunteers were treated initially with molecular iodine Study 3: 23 patients received molecular iodine, 007 to 009 mg/kg body weight; 33 received an aqueous mixture of brown vegetable dye and quinine The numbers in study 2 increased over the review period so that 1365 volunteers were being treated with molecular iodine by 1989 Interventions All patients in study 3 had pre- and post-treatment mammography and measurement of serum triiodothyronine, thyroxine and thyroid-stimulating hormone levels Main outcome measures Subjective evaluation--freedom from pain--and objective evaluation--resolution of fibrosis Results Study 1: 70% of subjects treated with sodium iodide had clinical improvement in their breast disease, but the rate of side effects was high; 40% of patients treated with protein-bound iodide had clinical improvement Study 2: 74% of patients in the crossover series had clinical improvement, and objective improvement was noted in 72% of those who received molecular iodine initially Study 3: in the treatment group 65% had subjective and objective improvement; in the control group there was a subjective placebo effect in 33% and an objective deterioration of 3% Conclusions The fibrocystic breast reacts differently to sodium iodide, protein-bound iodide and molecular iodine Molecular iodine is nonthyrotropic and was the most beneficial

Effect of solvent type on the determination of total iodine in milk powder and human serum by inductively-coupled plasma-mass spectrometry

Abstract: A method for the determination of the total iodine content in milk powder and human serum by inductively coupled plasma mass spectrometry is described. It is shown that the oxidation state of the analyte has a strong impact on the analytical performance. If iodine is present as iodide and nitric acid is used for acidification, the observed ion signal is not stable and samples spiked with iodide yield erroneous recoveries up to 750%. Hence, as the iodine in milk powder is present almost exclusively as iodide, destruction of the sample with nitric acid is not suitable. It was found that such an excessive spike recovery does not occur if ammonia solution instead of nitric acid is used as the diluent. The proposed sample preparation was tested by analysing three reference milk powders, namely Certified Reference Materials 150 and 151 Spiked Skim Milk Powder (from the Community Bureau of Reference) and Standard Reference Material 1549 Non-Fat Milk Powder (from the National Institute of Standards and Technology). Good agreement with the certified values was obtained, indicating that no significant errors are introduced. For human serum, samples treated with nitric acid or with ammonia solution gave results that were not significantly different from each other. Results are given for both a ‘second-generation’ biological reference material, Freeze-Dried Human Serum (University of Ghent), and for sera from healthy individuals.

L-Cysteine as a reducing and releasing agent for the determination of antimony and arsenic using flow injection hydride generation atomic absorption spectrometry—Part 1. Optimization of the analytical parameters

Abstract: L-Cysteine was investigated as the reducing and releasing agent for the determination of antimony and arsenic using flow injection hydride generation atomic absorption spectrometry with the aim of replacing the previously used potassium iodide. The prereduction of the pentavalent to the trivalent form at room temperature was completed within 5 and 30 min for antimony and arsenic, respectively, which was essentially identical with the performance of potassium iodide. However, much lower acid and reagent concentrations were required with L-cysteine than with potassium iodide. In addition, even dilute analyte solutions containing L-cysteine were stable for at least one week, whereas solutions containing potassium iodide had to be prepared fresh daily. Under optimized conditions, in the presence of 1% m/v L-cysteine and 1 mol l–1 HCI for antimony or 0.1 mol l–1 HCI for arsenic, detection limits (three times the standard deviation of a blank solution, n= 10) of 0.05 and 0.01 µg l–1 were obtained for antimony and arsenic. The calibration graphs were linear (r > 0.999) for up to 10 µg l–1 of antimony and 5 µg l–1 of arsenic, using integrated absorbance for evaluation. The precision was better than 2% relative standard deviation (n= 10) for both elements at the 5 µg l–1 concentration level.

Iodine/resin disinfectant and a procedure for the preparation thereof

Abstract: The present invention relates to iodine demand disinfectants. It relates in particular to a process for preparing a polyiodide-resin for use as a iodine demand disinfectant wherein a porous strong base anion exchange resin in a salt form, is contacted with a material capable of donating a member absorbable by the resin so as to convert the resin to the polyiodide-resin. The adsorbable member is selected from the group comprising I2 and polyiodide ion having a valence of -1. The process is characterized in that conversion of the anion exchange resin to the polyiodide-resin is effected at elevated temperature and elevated pressure, the elevated temperature being 100 °C or higher, the elevated pressure being greater than atmospheric pressure. The present invention also relates to a disinfectant substance comprising an iodine (impregnated) resin as produced by the above process.

Selenium deficiency aggravates the necrotizing effects of a high iodide dose in iodine deficient rats.

Abstract: The effect of selenium deficiency associated with various iodide intake was investigated in rats in order to better understand its possible role in the etiopathogeny of myxedematous cretinism. Groups of rat pups were fed from birth a low selenium diet (Se-) and submitted to goitrogenic treatment (1% perchlorate in water) for one month. Some animals were refed iodide after perchlorate withdrawal. The gland morphology was analyzed in correlation with the glutathione peroxidase (GPX) activity and the thyroid hormone plasma levels. In all Se- rats, the GPX activity was strongly reduced as compared to selenium sufficient (Se+) animals (P < 0.01). Goitrous rats were hypothyroid whatever the selenium intake. After iodide refeeding, plasma T4 and T3 levels were increased by 160% in Se- rats and by respectively 330% and 580% in Se+ rats. The thyroid morphology was different according to the selenium intake: necrotic cells were about three times more numerous in Se- than in Se+ rats (P < 0.01) and the inflammatory reaction was increased. These experimental data demonstrate the detrimental role of selenium deficiency in one experimental case of thyroid disease. Such reduction of cell defences could contribute to the thyroid failure of African myxedematous cretins.

Evidence of thyroid volume increase in normal subjects receiving excess iodide.

Abstract: A prospective study was conducted on 10 normal male volunteers to investigate the effect of the administration of excess iodide on thyroid volume. After 1 week of dietary iodide restriction, all subjects were given daily oral doses (27 mg daily total iodine dose) of licorice lecithin-bound iodine tablets for 4 weeks. Thyroid function studies, total serum iodine concentration, and urinary iodine excretion were monitored. Thyroid volume was measured by high resolution echoscanner before treatment, on the day of the last treatment, and 1 month after the treatment. There was a significant rise in serum TSH levels, with a small decline in serum free T4 concentration during iodide administration; the values remained within the normal range except for two subjects. Serum thyroglobulin levels were increased in parallel with serum TSH levels, which became higher than normal after 1 week of treatment. The volume of the thyroid gland became significantly enlarged after 28 days of iodide intake. When iodide was discontinued, thyroid volume and function returned to baseline levels within 1 month for all subjects. This is the first documentated objective evidence that the compensatory rise in serum TSH in response to iodide administration elicits reversible thyroid hypertrophy in normal subjects.

Speciation of iodo amino acids by high-performance liquid chromatography with inductively coupled plasma mass spectrometric detection

Abstract: High-performance liquid chromatography (HPLC) has been coupled with on-line inductively coupled plasma mass spectrometry (ICP/MS) for the speciation of iodide ion I - and five iodo amino acids (monoiodotyrosine, diiodotyrosine, 3,3',5- and 3,3',5'-triiodothyronine, and thyroxine) commonly found in thyroglobulin. The absolute detection limits were in a range from 35 to 130 pg as iodine: this is roughly 1 order of magnitude lower than those in conventional methods using stable isotope of iodine

Activated carbon adsorbent and applications thereof

Abstract: An alkali metal iodide and phosphoric acid are homogeneously supported on activated carbon, for example an activated carbon honeycomb, in respective amounts of 0.015 to 1.5 mg atoms as iodine and 1.4 to 7.0 mg equivalents per gram of activated carbon. The alkali metal iodide is, for example, potassium iodide. When both the chemicals are supported on activated carbon in amounts respectively within the above ranges, homogeneous supporting of phosphoric acid with the alkali metal iodide becomes possible without causing any decrease in adsorption and elimination capacities. A number of malodorous and harmful components such as nitrogen-containing compounds and sulfur-containing compounds can be efficiently removed with one kind of activated carbon over a long period of time. The activated carbon adsorbent thus obtained can be used for various deodorization purposes and in exhaust gas treatment, and is particularly suited for use in toilet deodorization and in gas treatment in closed spaces, for example in refrigerators.

Clinical evaluation of the iodide/creatinine ratio of casual urine samples as an index of daily iodide excretion in a population study.

Abstract: To assess the daily iodine intake in a population study, we have compared the validity and degree of reliability of the urine iodide/creatinine ratios and iodide concentrations of casual samples as a representative index of daily urine iodide excretion. The morning urine samples were obtained from apparently healthy 2,956 men and 1,182 women residing in Sapporo, Japan, and urine iodide was measured by an iodide selective electrode. The iodide/creatinine ratios was higher in women than in men, increasing more steeply with age in women than in men, due to a concomitant decrease in the urine creatinine level with age. The iodide concentration showed no age-related change. Similarly the daily urine iodide excretion measured in 22 control subjects by collecting 24-h urine specimens did not vary with age, while the iodide/creatinine ratio of these subjects increased with age. The correlation coefficient(r) of the iodide concentration with daily iodide excretion in the 95 observations of the 22 subjects was 0.832 (P < 0.001), higher than that of iodide/creatinine ratio with daily iodide excretion (0.699, P < 0.001). The 95% range of the iodide concentration in morning urine samples in the population (n = 4,138) was 9.0-70.3 mumol/L with a mean of 27.1 mumol/L.(ABSTRACT TRUNCATED AT 250 WORDS)

A stable carbene iodine adduct: secondary bonding in 1,3-diethyl-2-iodo-4,5-dimethylimidazolium iodide

Abstract: The stable carbene iodine adduct 2 is formed by the reaction of the imidazol-2-ylidene 1 with iodine; the X-ray structure of 2 is reported.

Use of activated carbon fiber for direct removal of iodine from acetic acid solution

Abstract: Activated carbon fiber was used as a new adsorbent for direct removal of iodine and iodide compounds from acetic acid solutions under static and dynamic conditions. In aqueous solution as well as in acetic acid, methanol, or ethanol, activated carbon fiber showed excellent iodine removal efficiency, superior to that of activated carbon, silica gel, alumina, NaY zeolite, Ag ion-exchanged NaY, and Ag ion-erchanged Amberlyst XN 1010. Water was a promoter for the removal of iodine on activated carbon fiber. The amount of iodine removed followed the reverse order of solubility of iodine in the solution. Activated carbon fiber could be used as an iodine removal adsorbent without significant change in the removal efficiency over a wide range of iodine concentration and contact time. The activated carbon fiber used was completely regenerated by He flushing above 200°C. In addition to the excellent iodine removal characteristics, activated carbon fiber showed a good performance in the removal of iodide compounds such as hydrogen iodide

Iodine deficiency in pregnancy in Denmark: Regional variations and frequency of individual iodine supplementation

Abstract: Iodine requirements are increased during pregnancy and lactation and adequate iodine intake is important for normal brain development of the fetus/newborn child. The aim of the present study was to evaluate the extent to which this increase in iodine requirement is met in pregnant women living in various regions of Denmark. One hundred and fifty-two healthy pregnant women admitted to five different Danish departments of obstetrics participated in the study. Iodine status was evaluated by measurement of iodine in spot urine at day five after delivery and by careful history of the intake of iodine containing vitamin/mineral tablets. Approximately one third of the women had received tablets containing iodine. In women who had not received iodine supplementation urinary iodine was low with a median value of 39.7 micrograms/g creatinine (Aalborg 28, Randers 33, Ringkobing 34, Arhus 43 and Copenhagen 62 micrograms/g creatinine). These values are far below internationally recommended levels. The consequences remain to be evaluated and no firm recommendations can be given. It seems reasonable, however, to recommend a high intake of food containing iodine (e.g. milk products) during pregnancy and lactation. Since nearly all the women took some kind of vitamin/mineral supplementation it could be considered to advocate intake of vitamin/mineral tablets containing iodine.

Treatment of amiodarone iodine-induced thyrotoxicosis with plasmapheresis and methimazole

Abstract: The present report illustrates the clinical and biochemical outcome in two amiodarone iodine-induced thyrotoxicosis (AlIT) patients submitted to plasmapheresis. Amiodarone was discontinued, and treatment with MMI (40 mg/day) was started. In addition, patients were submitted to two sessions of plasma-exchange, with a one-day interval between the two session. In both patients serum total T3 (TT3) and free T3 (FT3) concentrations decreased promptly but in contrast to the serum TT3, FT3 levels remained steadily above the normal range. A similar behaviour was observed for total T4 and free T4 plasma concentrations. Interestingly, a clearcut clinical amelioration was observed in both patients even before a reduction of circulating free thyroid hormone concentrations could be documented. In conclusion, our experience indicates that plasmapheresis may be useful in order to obtain a rapid amelioration of severe clinical picture of thyrotoxicosis, but cannot be considered as a definite therapy in AIIT. It should be considered that plasmapheresis is not devoid of risks and is also a very expensive procedure.

Use of potassium iodide as a chemical actinometer

Abstract: Aqueous solutions of KI were examined for use as chemical actinometers to measure 254 nm (germicidal) radiation. Irradiation results in electron ejection from iodide such that aqueous electrons and iodine atoms are formed. In the presence of N20, an electron scavenger, recombination of these two reactive species is eliminated and stoi-chiometric formation of triiodide occurs. The absorbance increase due to triiodide was followed and the quantum yield determined using either a radiometer or ferrioxalate actinometry to estimate the amount of energy absorbed by the KI solution. The quantum yield (o) at 25°C was determined to be 0.26 using radiometry, and 0.224–0.233 using actinometry, depending on the radiation conditions. The following expression was used to measure the incident Huence rate for 254 radiation at a given temperature T for irradiation over a time interval Δt (s) fluence rate (W/m2) = 4. 96 × 106ΔOD(λ)/ e(λ) [0.23+0.004(T-25)] δ t cm−1 At temperatures other than 25°C, the temperature dependence of the quantum yield (0.004/°C) is taken into account by the term shown in the denominator. Because KI remains relatively blind to longer wavelengths such as those found in normal room light, measurements can be made in the presence of room light without having to work in a darkened room.

The mythology of povidone-iodine and the development of self-sterilizing plastics.

Abstract: The predominance of elemental iodine as a chemical antiseptic has been established during a century. Free iodine is effective for treatment and prevention of infection. Iodophors, such as povidone-iodine, have replaced elemental iodine in clinical use. Toxic absorption of povidone-iodine occurs from all tissues except intact adult skin, to which its use should be restricted. Povidone-iodine binds iodine so firmly that insufficient free iodine is released to be effective for treating or preventing infection. It is a weak antiseptic that is marginally acceptable as a disinfectant for adult skin. The shortcomings of povidone-iodine stimulated a search for iodophors that would liberate therapeutically effective concentrations of free iodine. These investigations led to a new self-sterilizing plastic formed by the complexing of polyurethane and iodine.

Triiodide Ion-Selective Electrode Based on Manganese(III)-Tetraphenylporphine

Abstract: A new sensitive and selective electrode for triiodide ion has been developed. The electrode was constructed by incorporating Mn(III)-tetraphenylporphine into a plasticized poly(vinyl chloride) membrane. The electrode shows super-Nernstian response over the range 10-5 to 10-3M triiodide ion in the pH range of 2 to 9, with an anionic slope of 87 mV/ concentration decade. The electrode exhibits high specificity for triiodide ion over other anions (salicylate, benzoate, propionate, perchlorate, iodide, bromide, chloride, fluoride, nitrate and bicarbonate). The electrode has been applied to measure triiodide ion generated from iodine. The results have indicated that iodine can be determined by simple potentiometric measurements. A similar method may be applied to determine oxidizing agents, bromine and hydrogen peroxide, which oxidize iodide ion to iodine.

Determination of nanogram amounts of iodine in foods by radiochemical neutron activation analysis

Abstract: Three different neutron activation analysis methods have been developed for the determination of ppb levels of iodine in food samples. The methods are based on the separation of iodine using (i) toluene extraction followed by bismuth sulfide coprecipitation; (ii) bismuth sulfide coprecipitation followed by radiochemical purification with palladium iodide; and (iii) radiochemical isolation by bismuth sulfide coprecipitation. The accuracy of these methods was evaluated by analysing replicate samples of reference materials. The measured values of iodine in A-11 Milk Powder, H-4 Animal Muscle and H-9 Mixed Human Diet from the International Atomic Energy Agency (IAEA) are statistically indistinguishable from the IAEA recommended values, and those for the Standard Reference Materials 1571 Orchard Leaves and 1577 Bovine Liver from the National Institute of Standards and Technology (NIST) are in good agreement with the NIST information values. The precision, in terms of relative standard deviation, is 5% at 50–100 ppb and 10% at 5–20 ppb levels of iodine. The absolute detection limits of these methods vary between 0.5 and 10 ng of iodine. All three methods were used to measure the iodine content of several food samples. The method involving bismuth sulfide coprecipitation followed by radiochemical purification provides the best detection limit and highest precision.

Iodized salt prophylaxis of endemic goiter: an experience in Toscana (Italy)

Abstract: It is well established that iodine supplementation is effective in correcting iodine deficiency and reducing goiter prevalence. In Italy, legislation has allowed the production of iodized salt since 1972, but its consumption is on a voluntary basis. In the present study, the efficacy of legislative measures that made compulsory the availability of iodized salt in foodstores has been evaluated. Urinary iodine excretion and thyroid size, scored according to Pan American Health Organization recommendations, were determined prior to (1981) and 10 years after (1991) the introduction of legislative measures in the whole schoolchildren population residing in a restricted area of the Tuscan Appennines. Moreover, in 1991, thyroid volume was determined by ultrasonography. In 1981, mean urinary iodine excretion was 47.1 +/- 22.4 mg/kg creatinine (0.412 mumol/l) and goiter prevalence was 60%, indicating a moderate iodine deficiency. Eighty of the families subsequently used iodized salt on a regular basis; as a result of this excellent compliance, in 1991 the mean urinary iodine excretion increased to 129.7 +/- 73 mg/kg creatinine (1.24 mumol/l) and goiter prevalence dropped to 8.1%. The results of this study underline the effectiveness of iodine prophylaxis in correcting iodine deficiency and abating endemic goiter in schoolchildren, and suggest that implementation of measures that make compulsory the availability of iodized salt in foodstores overcomes the fact that there is no law governing the exclusive production and trading of iodized salt.