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Infants are in negative iodine balance on current standard regimens of total parenteral nutrition, with a mean iodine intake of 3 micro g/kg/day (150 ml/kg/day). The recommended enteral intake of iodine for preterm infants is 30 micro g/kg/day. Gastrointestinal absorption of iodine is high, suggesting that parenteral intakes should approach enteral recommendations.

Flavonoids have inhibiting effects on the proliferation of cancer cells, including thyroidal ones. In the treatment of thyroid cancer the uptake of iodide is essential. Flavonoids are known to interfere with iodide organification in vitro, and to cause goiter. The influence of flavonoids on iodine metabolism was studied in a human thyroid cancer cell line (FTC-133) transfected with the human sodium/iodide transporter (NIS). All flavonoids inhibited growth, and iodide uptake was decreased in most cells. NIS mRNA expression was affected during the early hours after treatment, indicating that these flavonoids can act on NIS. Pendrin mRNA expression did not change after treatment. Only myricetin increased iodide uptake. Apeginin, luteolin, kaempferol and F21388 increased the efflux of iodide, leading to a decreased retention of iodide. Instead myricetin increased the retention of iodide; this could be of use in the radioiodide treatment of thyroid cancer.

To understand the biogeochemical transfer of iodine, the absorbability and bioaccumulation of iodine in tested vegetables (radish, spinach and Chinese cabbage) are examined by applying iodic fertilizer composed of kelp and diatomaceous earth. The experimental results show that when iodine in soil is not excessive, the concentrations of iodine in tested vegetables increase as the content of iodine in soil increases. The absorbability and enrichment degree of iodine in various vegetables and in various parts of the same vegetable a redifferent, which explains that the concentration of iodine in plant is determined by the plant type and the physiological action of plant. The patience order of tested vegetables to excessive iodine is Chinese cabbage > spinach > radish. These results have theoretical and practical significance in opening up a new way for ameliorating poor iodine environment with artificial means.

The study was designed to examine the time-course of iodine elimination by hemodialysis to determine a desirable duration for dialysis after angiography to prevent contrast media nephropathy (CMN) in patients with renal failure. Reduction rates of iodine by hemodialysis (DRR) of 1 to 3 h and the renal elimination of iodine (RER) for 20 h after hemodialysis were prospectively examined in 8 chronic renal failure (CRF) patients. The mean DRR was 46.6% at 1 h, 65.2% at 2 h, and 75.1% at 3 h, and the mean RER was 49.4% in the CRF patients. Renal function significantly deteriorated in 2 CRF patients after angiography. Plasma iodine was eliminated by more than 80% after 2 h of hemodialysis following angiography, and the subsequent renal elimination in patients with mild-to-moderate renal failure was also examined. There is no need of prophylactic hemodialysis to prevent CMN for these patients when they have no additional risk factors such as a high dose of contrast medium, diabetes mellitus, or severe heart failure. However, 2 h of hemodialysis is desirable immediately after angiography for patients with moderate renal failure and one additional risk factor, and three hours or more of hemodialysis is also desirable for patients with severe renal failure, and for those with moderate renal failure having two or more additional risk factors.

An in vitro experimental system was devised to assess the direct effects of the goitrogen, potassium perchlorate (KClO(4)), on radioiodide uptake and organification by the larval lamprey endostyle. Organification refers to the incorporation of iodide into lamprey thyroglobulin (Tg). Histological and biochemical evidence indicated that endostyles were viable at the termination of a 4h in vitro incubation. A single iodoprotein, designated as lamprey Tg, was identified in the endostylar homogenates by polyacrylamide gel electrophoresis and Western blotting. Lamprey Tg was immunoreactive with rabbit anti-human Tg serum and had an electrophoretic mobility similar to that of reduced porcine Tg. When KClO(4) was added to the incubation medium, both iodide uptake and organification by the endostyle were significantly reduced relative to controls as determined by gamma counting, and gel-autoradiography and densitometry, respectively. Western blotting showed that KClO(4) significantly lowered the total amount of lamprey Tg in the endostyle. Based on the results of this in vitro investigation, we conclude that KClO(4) acts directly on the larval lamprey endostyle to inhibit thyroidal activity. These data support a previous supposition from in vivo experimentation that KClO(4) acts directly on the endostyle to suppress the synthesis of thyroxine and triiodothyronine, resulting in a decrease in the serum levels of these two hormones., (Copyright 2002 Elsevier Science (USA))

Transport of iodine in the mammary gland into breast milk plays a central role in various fields of prevention of thyroid diseases. First, a sufficient content of iodine in the mother's milk is necessary for normal brain development in the breastfed child. This is attained by expression during lactation in the mammary gland of the sodium iodide symporter (NIS), also responsible for iodine transport in the thyroid. Milk iodine content varies with the iodine intake of the mother, and urinary iodine excretion in groups of mothers seems to be a valuable indicator of the iodine status of their breastfed children. Second, iodine in dairy products provides a considerable part of iodine intake in many populations. Thiocyanate from rapeseed feeding of cows decreases milk iodine content, probably by competitive inhibition of NIS in the mammary gland. Alterations in feeding of dairy cows may alter the iodine content of consumer milk, and this may influence the risk of thyroid diseases in the population. Thiocyanate inhibition of iodine transport into milk may also be operative in humans with a high thiocyanate intake. This could further impair iodine status in breastfed children in low-iodine intake areas of the world. It can be speculated that a low-iodine content of mother's milk because of inhibition of NIS in the mammary gland may be one factor of importance for development of myxedematous cretinism.

Research on iodine metabolism was reviewed with special reference to short-term processes, pregnancy, and lactation. A detailed discussion of the new physiologically-oriented biokinetic model and a model parameterization procedure are given. Predictions of the new model are applicable for the analysis of in vivo and in vitro clinical data gained using iodine or radioactive tracers, as well as for the assessment of radiation exposure doses to mothers and offspring. The model can be used to simulate biokinetic processes in the human body, for prediction of biokinetic parameters such as the time course of thyroid uptake (both for mother and fetus), the rate of exertion with urine, and the level of iodine secretion with saliva and breastmilk. The structure of the model is applicable in a wide range of stable iodine in the diet, both for pregnant and non-pregnant persons.

Radioiodine therapy is now the most common definite treatment for persistent hyperthyroidism. The outcome of radioiodine therapy depends mainly on the absorbed energy dose in the diseased thyroid tissue. The administered activity and the resulting target dose in the thyroid depend on both the biokinetics of radioiodine and the actual therapeutic effect of radioiodine in the thyroid. Thyrostatic drugs have a major influence on the kinetics of radioiodine in the thyroid and may additionally have a radioprotective effect. Pre-treatment with thyrostatic medication lowers the effective half-life and uptake of radioiodine. This can reduce the target dose in the thyroid and have a negative influence on the outcome of the therapy. Discontinuation of medication shortly before radioiodine administration can increase the absorbed energy dose in the thyroid without increasing the whole-body exposure to radiation as much as would a higher or second radioiodine administration. Furthermore, administration of non-radioactive iodine-127 2-3 days after radioiodine administration can also increase the effective half-life of radioiodine in the thyroid. Thus, improving the biokinetics of radioiodine will allow lower activities to be administered with lower effective doses to the rest of the body, while achieving an equally effective target dose in the thyroid.

In order to determine whether the iodine intake influences the diagnostic power of ultrasound-guided fine-needle aspiration cytology (US-FNAC), patients with nontoxic nodular goiter from an area with sufficient iodine intake (IS) (n = 938, median iodine excretion [MIE] = 103 microg/L) and from an iodine-deficient (ID) area (n = 3,601, MIE = 75 microg/L) were investigated. Elevated rates of multinodularity (59.6% vs. 49.6%, p < 0.001), nonpalpable nodules (47.6% vs. 37.3%, p < 0.001) and nondiagnostic US-FNACs (8.8% vs. 5.1%, p = 0.008), and a lower malignancy rate (1.2% vs. 2.3%, p = 0.006) were found in the ID area. Follicular tumors were encountered among positive findings. Cytohistologic comparison (ID, n = 416; IS, n = 97) revealed that the sensitivity, specificity, and diagnostic accuracy of US-FNAC were similar in the two areas (95.5% vs. 92.3%, 78.3% vs. 71.1%, 82.4% vs. 80.6%, IS vs. ID area, respectively), while a lower malignancy rate and a higher ratio of benign to malignant tumors were observed in the ID than in the IS area (10.1% vs. 22.6%, p < 0.001, and 4.38 vs. 1.50, p < 0.001, respectively). This resulted in a lower positive predictive value of US-FNAC in the ID (36/106) than in the IS area (21/36, p = 0.001), because the rate of false US-FNAC was higher in benign (67/184) than in malignant tumors (4/61, p < 0.001).

Unlabelled: Low 24-hour thyroid uptake of I-131 (I-131 uptake) is a common finding that influences evaluation of the thyroid gland., Methods: We studied 20 female patients aged 16-82 years with low I-131 uptake. The following causes of reduced I-131 uptake were defined as (A) six cases with subacute thyroiditis, (B) seven cases with T4 suppression therapy, and (C) seven cases with iodinated pharmaceuticals use. Thirty-minute Tc-99m tetrofosmin thyroid scan was performed within 24 hours of the I-131 thyroid study., Results: The results were correlated with neck ultrasound, serum TSH and biopsy histopathological findings. Tc-99m tetrofosmin thyroid scans revealed 10 normal thyroids, five diffuse goiters, four multinodular goitres, and one solitary thyroid nodule., Conclusions: Our results suggest that Tc-99m tetrofosmin thyroid scans may provide additional information to diagnose thyroid pathology in patients with low 24-hour I-131 uptake.

A significant impact of high bromide levels in the organism of the mother on iodine transfer to the sucklings was established in experiments with female Wistar rats. The observed decrease in iodine transfer to the young through mothers' milk and/or an increase in the bromide concentration in the milk, caused a decrease in body weight of the pups. Enhanced bromide levels also adversely affected the thyroid gland of the young. High bromide intake in the lactating dams caused a decrease in iodide accumulation in the mammary glands, and also an increase in iodide elimination through the kidneys.

The major procedure used to correct iodine deficiency is the universal salt iodization by addition of iodide or iodate to salt with an iodine content varying from 7 to 100 mg/kg of salt depending on the country legislation. As an important fraction of consumers in the world prefers natural products over artificial ones, we investigated the industrial feasibility of naturally iodized salt using seaweed as source of iodine. We report the results of the iodine bioavailability in healthy subjects from two seaweeds: Laminaria hyperborea and Gracilaria verrucosa selected due to their high level in iodine as a mineral or an organic form and low levels of heavy metals. As a control we studied in a normal man the bioavailability of pure mineral iodine such as potassium iodide which was excellent i.e. 96.4% and of pure organic iodine such as monoiodotyrosine which was a little lower i.e. 80.0%. Iodine bioavailability from these two seaweeds was studied in nine normal subjects from Marseille (France) which is an iodine sufficient area based on a median urinary iodine level of 137 microg/day and innine normal subjects from Brussels (Belgium) who present a mild iodine deficiency with a value of 73 microg/day. The iodine bioavailability of Gracilaria verrucosa is better than for Laminaria hyperborea (101% versus 90% in Marseille, t=0.812, NS; 85% versus 61.5% in Brussels, t = 2.486, p = 0.024, S*). The urinary excretion of iodine is lower in Brussels than in Marseille for the same seaweed because part of the iodine is stored in the thyroid (101% versus 85% for Gracilaria verrucosa, t = 1.010, NS; 90% versus 61.5% for Laminaria hyperborea, t = 3.879, p= 0.001, S***).

The Pendred syndrome gene encodes a 780-amino acid putative transmembrane protein (pendrin) that is expressed in the apical membrane of thyroid follicular cells. Although pendrin was shown to transport iodide and chloride using Xenopus laevis oocytes and Sf9 insect cells, there is no report using mammalian cells to study its role in thyroid function. We show here, using COS-7 cells and Chinese hamster ovary cells transfected with expression vectors encoding sodium iodide symporter or human Pendred syndrome gene cDNA and by comparison with studies using rat thyroid FRTL-5 cells, that pendrin is an iodide-specific transporter in mammalian cells and is responsible for iodide efflux in the thyroid.

Rationale and Objectives: To assess a surface-modified emulsion as a percutaneous CT lymphographic agent in normal dogs., Methods: An iodinated chylomicron remnant-like microemulsion was formulated with a mean particle size of 91.3 nm and an iodine concentration of 91 mg I/mL. Contrast material (2 mL) was injected into the subcutaneous tissues of the metatarsus and metacarpus of six normal dogs to enhance popliteal and cervical lymph nodes, respectively. CT images were acquired at 0, 15, 30, 45, 60, 240, 480, and 1440 minutes., Results: Significant lymph node enhancement occurred in as little as 15 minutes after injection and persisted at least 8 hours. Node opacification was most pronounced at 1 to 4 hours postinjection and exceeded 200 HU in some nodes (precontrast attenuation = 45 HU). Marked enhancement of popliteal efferent lymphatics and of iliac and sacral node groups also occurred indicating distribution to second order nodes. Attenuation of enhanced nodes reverted to precontrast levels by 24 hours., Conclusion: The new surface-modified, chylomicron remnant-like emulsion provided marked, selective enhancement of targeted lymph nodes after subcutaneous administration. Moreover, the formulation produced significant opacification of more distant node groups from a single injection.

Objective: The pharmacokinetics of iopromide were analysed using a two-compartment model. The optimal point of time for blood withdrawal for calculation of a one-sample clearance was determined., Methods: Plasma concentration of iodine was measured up to 8 h postinjection (p.i.) in 62 adult patients who received 120 ml iopromide for computed tomography (CT). A two exponential function was fitted by a weighted least error square method. As reference method, clearance was calculated from this function and the injected amount of iodine. Empirical parameters for calculation of one-sample clearance were determined. This one-sample clearance was compared with one-sample clearance calculated according to formulas developed for Tc99m-DTPA by Jacobsson as well as a two sample method., Results: Total distribution volume of iopromide was calculated as 0.242 Lkg(-1)+/- 5.9%. A high correlation of all one-sample method and the two-sample method with reference to clearance was found. Best estimation of iopromide plasma clearance was achieved by determining one-sample clearance 270 or 285 min p. i. with SD(y.x) of 5.8 ml min(-1)., Conclusions: After administration of 120 ml iopromide, one-sample plasma clearance can be calculated with low estimation error taking one blood sample at an appropriate time point. Late phase pharmacokinetics of iopromide found in the present study showed to be virtually identical to results published for iohexol and Tc99m-DTPA.

In the developing countries of Africa, many children are at high risk for both goiter and iron-deficiency anemia (IDA). Because iron (Fe) deficiency can have adverse effects on thyroid metabolism, Fe deficiency may influence response to supplemental iodine in areas of endemic goiter. Therefore, our aims were to determine: 1) if goitrous children also suffering from IDA could respond to oral iodine supplementation; and 2) if Fe supplementation in goitrous children with IDA would improve their response to oral iodized oil and iodized salt. First, we compared the efficacy of oral iodized oil in two groups of goitrous children: a nonanaemic group vs. an IDA group. The therapeutic response to iodized oil was impaired in the goitrous children with IDA. Second, an open trial of Fe treatment in goitrous children with IDA improved their response to oral iodized oil. Finally, in a randomized double-blind trial, goitrous, Fe-deficient children consuming iodized salt were given Fe supplementation or placebo. Fe supplementation improved the efficacy of the iodized salt. In these studies, both anatomic (thyroid size) and biochemical (TSH, T4) measures indicated that iodine significantly improved thyroid function in the nonanaemic children compared to the Fe deficient children. Iodine was less efficacious in children with lower Hb at baseline and in those with a poorer response to Fe. The data suggest that a high prevalence of IDA among children in areas of endemic goiter may reduce the effectiveness of iodine prophylaxis.

Starting from different regional samples taken from a heterogeneous follicular thyroid cancer recurrence in a male patient, a series of cell cultures was initiated. Three stable cancer cell lines were successfully established (TT2609-A02, TT2609-B02, and TT2609-C02) and kept in continuous culture for more than 3 years. The lines are each characterized by a unique set of biological parameters such as morphology, ploidy state, cell proliferation rate, ultrastructure, thyroid marker expression, p53 expression, karyogram, agar clonogenic capacity and tumorigenicity as xenografts in nude mice. These characterization studies point to a marked heterogeneity at the level of the clinical tumor recurrence. Karyotype analysis of the cell lines showed a pattern of aberrations indicating that the lines are clonally related and that the A02 and C02 lines are subsequently derived from the more "original" tumor cell type B02 after a tetraploidization event. It is concluded that the obtained cell lines represent an in vitro/in vivo model for human follicular thyroid cancer. The availability of a series of cell lines for human follicular thyroid cancer, mimicking the biological heterogeneity observed in patient tumors, enables both detailed fundamental investigation of thyroid cancer cell biology and the experimental exploration of new treatment approaches.

The effect of the phorbol esther phorbol myristate acetate (PMA) on iodide uptake was studied in primary cultures of calf thyroid cells. PMA caused a dose- and time-dependent inhibition of thyrotropin (TSH), forskolin, and db-cAMP stimulation, indicating an effect distal to both TSH receptor and cAMP generation. No action was found on iodide efflux, indicating a selective inhibition of iodide uptake. This inhibition was observed even after 5 minutes of incubation, thus excluding a possible genomic action. Bisindolmaleimide (BS), a specific inhibitor of the protein kinase C (PKC) pathway, reverted the effect of PMA. A similar degree of inhibition of the Na+/K+ adenosine triphosphatase (ATPase) and iodide uptake by PMA was found, thus suggesting a link between both parameters. These results indicate that the PKC pathway inhibits thyroid iodide uptake by an action distal to cAMP generation and probably because of a decrease in Na+/K+-ATPase activity.

Is the fetal thyroid already capable to increase its iodide uptake in response to iodine deficiency? To answer this question, we analyzed the expression of the Na(+)/I(-) symporter and several other genes in the thyroid of rat fetuses at 21 d of gestation from control mothers presenting a mild or more severe iodine deficiency. Female rats were placed on a low iodine diet, not supplemented, or supplemented with iodide or perchlorate for 3 months. The maternal and fetal thyroidal iodide uptake was measured 24 h after injection of 10 microCi Na (125)I into the dams. The absolute iodide uptake of the maternal thyroid was unchanged in a low iodine diet, not supplemented, compared with one supplemented with iodide. In contrast, the fetal thyroid absolute iodide uptake of a low iodine diet, not supplemented, and one supplemented with perchlorate was decreased by 70% and 95% compared with that supplemented with iodide. Na(+)/I(-) symporter mRNA was detected in the fetal thyroid of supplemented with iodide and increased about 2- and 4- fold in the thyroid of fetuses from a low iodine diet, not supplemented, and one supplemented with perchlorate, respectively. Na(+)/I(-) symporter expression was induced in the fetal side of the placenta in both a low iodine diet, not supplemented, and one supplemented with perchlorate; in contrast, Na(+)/I(-) symporter mRNA was never detected in the maternal side of the placenta. Fetal thyroid thyroglobulin and type I deiodinase mRNA contents were only significantly increased with a diet supplemented with perchlorate. Glucose transporter 4 mRNA was decreased in the fetal thyroid of both a low iodine diet, not supplemented, and one supplemented with perchlorate compared with one supplemented with iodide. In conclusion, although the up-regulation of Na(+)/I(-) symporter expression in fetal thyroid and placenta in the low iodine diet, not supplemented group did not lead to restoration of a normal absolute iodide uptake, our data show that all adaptive and/or defending mechanisms against iodine deficiency are already present in the fetus.

Total body iodine content was estimated in six normal young men, who underwent 125I balance studies during 64-92 days of daily 125I administration. Total body retention of 125I was measured as the difference between total administered 125I and that collected in the urine and feces. Extrathyroidal 125I was the difference between total and thyroidal 125I content. The time-activity data for the ratio of extrathyroidal to total retained 125I were fitted to a growth (inverse exponential) function. Fits of this growth function to the individual data sets yielded asymptotes, the equilibrium extrathyroidal/total 125I ratios. The slopes of this function predicted the time that would have been required to achieve 125I/127I equilibration (approximately 10 months). Geometric mean for the asymptotic extrathyroidal/total 125I ratio was 0.34 (range, 0.19-0.63), if it was assumed that measured urine and feces represented all of the 125I lost to the body. If 90% measurement of 125I loss was assumed, the geometric mean ratio was 0.32 (range, 0.17-0.60). Assuming that 90% of total loss is reflected in measured excreta and that total iodine content of the thyroid gland is 10 mg, geometric mean for total body iodine in these subjects was 14.6 mg (range, 12.1-25.3 mg).

Objectives: The aim of this project was to assess the clinical significance of our low iodine excretions in terms of thyroid hormone status and thyroid volume in an adult population in a low soil iodine area of the South Island of New Zealand., Design and Setting: Two-hundred and thirty-three residents of Otago, New Zealand collected two 24 h urine samples for assessment of iodine status. Thyroid status was determined from serum total T(4), TSH and thyroglobulin, and thyroid volumes. Relationships between urinary iodide excretion and measures of thyroid status were determined and subjects were allocated to one of three groups according to low, medium and high iodide excretion, for comparison of thyroid hormones and thyroid volumes., Results: Significant correlations were found for relationships between measures of urinary iodide excretion and thyroid volume and thyroglobulin. Multiple regression analysis of data for subjects divided into three groups according to 24 h urinary iodide excretion (<60, 60-90; >90 microg iodide/day) or iodide/creatinine ratio (<40; 40-60; >60 microg/g Cr) showed significant differences in thyroid volume (P=0.029; P=0.035, respectively) and thyroglobulin (P=0.019; P=0.005, respectively) among the groups., Conclusions: The results of this study confirm the low iodide excretions of Otago residents, and indicate that the fall in iodine status is being reflected in clinical measures of thyroid status, including enlarged thyroid glands and elevated thyroglobulin. Our observations suggest the possible re-emergence of mild iodine deficiency and goitres in New Zealand. This situation is likely to worsen should iodine intakes continue to fall and continued monitoring of the situation is imperative.

To cast light on whether xylazine hydrochloride (XZ), a veterinary medicine commonly used as a sedative agent for food-producing animals, has any promoting potential for thyroid carcinogenesis, the following studies were performed. In Experiment I, male F344 rats received a diet containing 1000 or 0 p.p.m. XZ for 52 weeks with or without initiation with 2400 mg/kg N:-bis(2-hydroxypropyl)nitrosamine (DHPN). Focal follicular cell hyperplasias, adenomas and/or carcinomas were induced in the DHPN alone, XZ alone and DHPN+XZ groups, and the incidences and multiplicities of these lesions in the DHPN+XZ group were significantly increased as compared with the DHPN alone case. In Experiment II, male F344 rats received a diet containing 1000 or 0 p.p.m. XZ and were examined for serum levels of triiodothyronine (T(3)), thyroxine (T(4)) and thyroid-stimulating hormone (TSH) at weeks 1, 2 and 4. In the XZ group, significant increase in thyroid weight and decrease in serum T(4) levels were observed at all time points. Serum T(3) and TSH levels were significantly decreased and increased, respectively, at week 1, but returned to within the control range thereafter. In Experiment III, male F344 rats received a diet containing 1000 or 0 p.p.m. XZ, they were examined for thyroid iodine uptake and organification of XZ after 1 and 2 weeks. The thyroidal iodine uptake per milligram of thyroid and the amount of iodine bound to 1 mg protein showed a tendency for decrease at week 1 and significant decrease at week 2. These results indicate that XZ has tumor-promoting effects on thyroid follicular cells, and suggest an involvement of alterations in thyroid-related hormone levels due to inhibition of thyroid iodine uptake and organification, resulting, provably, in serum TSH stimulation depending on continuous reduction of serum T(4) level through the feedback system in the pituitary-thyroid axis.

Recombinant human TSH (rhTSH), usually given as 0.9-mg doses im on 2 successive days, increases serum thyroglobulin (Tg) and radioactive iodine uptake (RAIU) in residual thyroid tissue in patients with thyroid cancer. We previously reported that a single, relatively low dose of rhTSH (0.1 mg im) is a potent stimulator of T(4), T(3), and Tg secretion in normal subjects. The present study describes the effects of higher doses of rhTSH on thyroid hormone and Tg secretion. Six normal subjects for each dose group, having no evidence of thyroid disease, received either 0.3 or 0.9 mg rhTSH by im injection. Serum TSH, T(4), T(3), and Tg concentrations were measured at 2, 4, and 8 h and 1, 2, 3, 4, and 7 days after rhTSH administration. The peak serum TSH concentrations were 82 +/- 18 and 277 +/- 89 mU/L, respectively, for the 0.3- and 0.9-mg doses of rhTSH. Serum T(4), T(3), and Tg concentrations increased significantly in subjects receiving 0.3 and 0.9 mg rhTSH, with significant increases in T(4) and T(3) being observed before significant increases in serum TG: Peak concentrations of serum T(4), T(3), and Tg, after 0.3 mg rhTSH administration, were 100 +/- 19, 131 +/- 14, and 1035 +/- 724% above individual baselines, respectively. Similarly, peak concentrations of serum T(4), T(3), and Tg, after 0.9 mg rhTSH administration, were 102 +/- 16, 134 +/- 7, and 1890 +/- 768% above individual baselines, respectively. These data, compared with previously reported data for the responses to 0.1 mg rhTSH, indicated that 0.1, 0.3, and 0.9 mg rhTSH had similar quantitative stimulatory effects on thyroid hormone and Tg secretion, except that the T(4) response was greater in groups receiving 0.3 and 0.9 mg rhTSH than in the group receiving 0.1 mg rhTSH. We also studied the effect of rhTSH on the thyroid RAIU in the group that received 0.9 mg rhTSH. The 6- and 24-h RAIU values were significantly higher after rhTSH (pre-rhTSH, 6-h value = 12.5 +/- 1.8%; 24 h value = 23 +/- 2.7%; post-rhTSH, 6 h value = 27 +/- 4.8%; 24-h value = 41 +/- 4.2%). The stimulating effects of 0.9 mg rhTSH on the 6- and 24-h RAIUs were similar. rhTSH is a potent stimulator of T(4), T(3), and Tg secretion and the RAIU in normal subjects. Single doses greater than 0.1--0.3 mg do not seem to further enhance thyroid hormone or Tg secretion.

Background: Universal salt iodization was introduced in Delhi in 1989. The present study quantifies the change in iodine kinetics as a result of this. The previous values were reported 10-30 years earlier, when Delhi was iodine deficient., Methods: Thirty subjects (18 men and 12 women, 17-48 years of age) who were residents of Delhi and had no thyroid disorder, were recruited from our outpatient clinic in 1999. The 24-hour urinary excretion of iodine and the iodine content of salt consumed at home by these subjects were estimated. Kinetic studies of iodine using radiotracer 131I were done to determine thyroid iodine clearance, renal iodine clearance, percentage uptake and absolute iodine uptake by the thyroid gland, and plasma inorganic iodine., Results: The median 24-hour urinary iodine excretion was 341.3 micrograms. The mean (SD) thyroid uptake of radioactive iodine was 4.9 (2.3)% at 2 hours and 19.1 (8.0)% at 24 hours. The median calculated plasma inorganic iodine was 1.36 micrograms/dl, absolute iodine intake 6.5 micrograms/hour and thyroid iodine clearance was 4.8 ml/minute (geometric means 1.68 micrograms/dl, 8.5 micrograms/hour and 8.1 ml/minute, respectively). The serum thyroid hormones and thyroid stimulating hormone were within normal limits., Conclusion: Compared to the values reported 10-30 years ago when the population was iodine deficient, the present urinary iodine excretion, plasma inorganic iodine and absolute iodine intake have increased, while the percentage thyroid uptake of iodine ingested and thyroid clearance have decreased. The lack of change in the serum thyroid hormone levels after 10 years of universal salt iodization indicates that iodine consumption has had no adverse effect on thyroid function in these normal individuals. These changes are consistent with the increase in iodine consumption. Since the iodine ingestion in a community may change with time, assessment of iodine kinetics should be done periodically in different regions of the country.

The concentrations of iodine in cereal grains cultivated at 38 locations in Austria from cereal-producing sites in agricultural areas and soil-to-grain transfer factors (TF) were determined. The concentrations of iodine in cereal grains, which were analyzed by radiochemical neutron activation analysis ranged from 0.002 to 0.03 microg g(-1), the arithmetic mean and the median were 0.0061 microg g(-1) and 0.0046 microg g(-1), respectively. The TF values for cereal grains were calculated to be 0.0005-0.02 and the median was 0.0016. The TF values correlated positively with the iodine concentrations in cereal grains. However, the TF values correlated negatively with the iodine concentrations in soils as well as with the amount of clay contents of soils. The TF values were almost independent on pH values (5.4-7.6) of soils.

Abnormally low(131)I uptakes were noticed in dogs fed with commercial diets at the University Animal Clinic in Buenos Aires, but the total iodine content of eight different commercial diets examined was found to provide an iodine intake above daily requirements. To investigate this anomaly, 18 dogs were distributed into three groups, fed either: (1) a home-prepared diet; (2) a commercial diet; (3) a home-prepared diet supplemented with potassium iodide equivalent to that found in the commercial diet. The(131)I uptake in dogs of groups B and C was significantly decreased, as was basal serum thyroxine (T(4)) and free thyroxine (FT(4)), whereas urinary iodide excretion and serum thyroid stimulating hormone (TSH), were increased. The thyroid releasing hormone (TRH)-TSH test showed an increased response in dogs from group B, while the TRH-T(4)test was inhibited in both groups B and C. The results demonstrate that the excessive amount of iodine present in some commercial diets in Argentina causes a significant impairment of thyroid function and hypothyroidism., (Copyright 2001 Harcourt Publishers Ltd.)

Adverse reactions to iodinated contrast media (ICM) are more likely to develop in patients with asthma, a history of allergy or contrast reaction and in those who are debilitated or medically unstable. These reactions can be divided into renal and general, and the latter are subdivided into acute and delayed. Acute general reactions can be minor, intermediate or severe. Fatal reactions are rare. The introduction of low-osmolality agents has caused an overall reduction in the number of non-fatal contrast reactions. Prompt recognition and treatment of acute adverse side effects to ICM is invaluable and may prevent a reaction from becoming severe. Familiarity with cardiopulmonary resuscitation is essential for successful management of life-threatening reactions. Contrast-media-induced renal impairment can be reduced with the use of low-osmolality contrast media and extracellular volume expansion. The use of ICM in diabetic patients receiving metformin should be carried out with care to avoid metformin-induced lactic acidosis. However, this problem is mainly observed in patients with diabetic nephropathy.

During the last decade the iodine supply in Germany has increased significantly, but there is still a high frequency of goitre. Therefore the question of iodine bioavailability has arisen. In a two-period study 12 women were given a mixed diet of ordinary foods with milk and milk products of different batches. None of the volunteers suffered from an iodine deficiency according to WHO-criteria. Each period ended with a 9-day balance-study protocol in which all foods were provided. Food and fluid intake were registered, and urine and faeces were quantitatively collected. The iodine content was determined by ICP-MS. The mean intake in the form of solid food amounted to 175 +/- 10 micrograms I/d and to 27 +/- 15 micrograms I/d in fluid form. Milk and dairy products represented the main source of iodine (37%). Iodine was predominantly excreted in the urine (89%, 171 +/- 45 micrograms I/d) and the faeces 11% (20 +/- 11 micrograms I/d). The resulting iodine balance was approximately . In one case an iodine-rich erythrosine preparation with a low iodine bioavailability was used. Between the two periods of consuming different batches of milk and milk products no differences were observed concerning the high bioavailability of iodine.

Purpose: To evaluate the effects of contrast media pharmokinetic differences on aortic enhancement at abdominal CT angiography and to determine whether these effects are of clinical relevance., Material and Methods: Two hundred and twelve patients referred for abdominal CT angiography were included in the study. All abdominal CT angiograms were performed with the same parameters (collimation 3 mm, pitch ratio 1.7, scan delay 30 s) after i.v. injection of 120 ml of contrast medium at 3 ml/s. After randomization, patients received either iobitridol 300 (low-osmolar, 300 mg I/ml), iobitridol 350 (low-osmolar, 350 mg I/ml) or ioxithalamate 350 (high-osmolar, 350 mg I/ml). The time attenuation curves obtained with the three contrast media were compared., Results: The time attenuation curve obtained with ioxithalamate 350 was not parallel to those obtained with iobitridol 300 and iobitridol 350. Mean peak enhancements obtained with iobitridol 350 and ioxithalamate 350 were not significantly different but iobitridol 350 provided higher mean peak enhancement than iobitridol 300. Mean delays of the peak enhancements were the same with the three contrast media. After peak enhancement, the decrease of aortic opacification under a selected threshold of 200 HU was significantly slower with iobitridol 350 than with iobitridol 300 and ioxithalamate 350, whereas iobitridol 300 and ioxithalamate 350 showed no significant differences., Conclusion: For a given iodine concentration, low-osmolality contrast media provide longer aortic opacification and may be recommended for CT angiography when long acquisition times are needed.

Purpose: Povidone-iodine is a commonly used intrarectal tumoricidal agent in patients undergoing colorectal surgery. The aim of this study was to assess systemic absorption of total iodine and its effect on thyroid function after intrarectal application., Methods: Twenty patients with carcinoma of the rectum received intraoperative irrigation with either povidone-iodine (Group A; n = 10) or physiologic saline (Group B; n = 10). Ten patients with carcinoma of the sigmoid colon (group C) were treated the same as Group A. Electrolyte, total iodine, triiodothyronine, thyroxine, and thyroid-stimulating hormone values were measured in serum preoperatively and before intraoperative irrigation and immediately, ten minutes, 1 hour, 6 hours, 24 hours, and two weeks after irrigation., Results: No significant changes occurred in serum electrolytes. A significant uptake of the total iodine was demonstrated in each group. Total iodine levels examined immediately, ten minutes, and one hour after irrigation in Group C were significantly higher than those examined in Group B. Maximum values were obtained one hour after irrigation in Groups A and B and six hours after irrigation in Group C. No significant changes occurred in triiodothyronine, thyroxine, and thyroid-stimulating hormone levels among the three groups. The decrease in triiodothyronine levels after surgery was demonstrated in each group. We noted a decrease after surgery in thyroxine levels for Groups A and B and in thyroid-stimulating hormone levels for Group B. Those hormones were not affected by the administration of povidone-iodine., Conclusion: High serum levels of iodine did not cause organ toxicity, suggesting that a single use of intraoperative bowel irrigation with povidone-iodine may be performed with practically negligible risk.

The PDS gene encodes a transmembrane protein, known as pendrin, which functions as a transporter of iodide and chloride. Mutations in this gene are responsible for Pendred syndrome and autosomal recessive non-syndromic hearing loss at the DFNB4 locus on chromosome 7q31. A screen of 20 individuals from the midwestern USA with non-syndromic hearing loss and dilated vestibular aqueducts identified three people (15%) with PDS mutations. To determine whether PDS mutations in individuals with Pendred syndrome differ functionally from PDS mutations in individuals with non-syndromic hearing loss, we compared three common Pendred syndrome allele variants (L236P, T416P and E384G), with three PDS mutations reported only in individuals with non-syndromic hearing loss (V480D, V653A and I490L/G497S). The mutations associated with Pendred syndrome have complete loss of pendrin-induced chloride and iodide transport, while alleles unique to people with DFNB4 are able to transport both iodide and chloride, albeit at a much lower level than wild-type pendrin. We hypothesize that this residual level of anion transport is sufficient to eliminate or postpone the onset of goiter in individuals with DFNB4. We propose a model for pendrin function in the thyroid in which pendrin transports iodide across the apical membrane of the thyrocyte into the colloid space.

Balance experiments have demonstrated that growing pigs fed a ration consisting of wheat, barley, extracted soya meal, dicalciumphosphate, and iodine-free feeding salt utilised 48.8% of the received iodine. The tested supplementary iodine sources included potassium iodide (KI), ethylenediamine dihydroiodide (EDDI), iodine humate (HUI) prepared from iodine acid (HIO3), and the product P containing 0.004% iodine in an oil base (P). The amount of the supplemented iodine was in all cases 1 mg per 1 kg feed. The utilisation of iodine from the supplements reached 93.6, 92.6, 90.7, and 67.9% for KI, EDDI, P, and HUI, respectively. The values were significantly higher compared with controls (P < 0.01). Compared with KI and EDDI, the utilisation of iodine from HUI was significantly lower (P < 0.01). The lower availability of iodine from HUI was probably due to the high binding capacity of humate. The amount of urinary iodine excreted by control pigs receiving in the non-supplemented ration 147.5 micrograms iodine per day, was 40.3 micrograms per day (27.3%). In the pigs receiving in the supplemented ration 1647.5 micrograms iodine per day, the amount of urinary iodine reached 734.9 to 805.0 micrograms per day (44.6 to 48.9%). The corresponding values of faecal excretion were 75.6 micrograms iodine per day (51.2%) for the control pigs and 106.2 to 121.1 micrograms iodine per day (6.45 to 7.35%) for the pigs fed the supplemented rations. A high amount of 528.6 micrograms iodine per day (32.1%) was excreted in the faeces by pigs of the group HUI.

Aim: We investigated whether additional application of "cold" iodine after therapy with radioiodine could result in a prolongation of the effective half life of iodine-131 and would thus lead to an increase of the effective thyroid radiation dose., Methods: Time-activity-curves after therapy with radioiodine were analysed in 25 patients (16 women, 9 men). Nine patients suffered from autonomously functioning thyroid nodules, 5 from autonomous multinodular goiter and 11 from Graves' disease. These patients had an effective half life shorter than 4 days resulting in an undertreatment of > 20% with respect to the desired effective thyroid radiation dose. 2-4 days after therapy with radioiodine all patients received "cold" iodine for three days in a dose of 3 x 200 micrograms per day., Results: In 14 of the 25 patients an increase of the effective half life was observed. Patients with an autonomously functioning thyroid nodule showed a mean increase of the effective thyroid radiation dose of 40 +/- 44 Gy, patients with toxic multinodular goiter of 29 +/- 30 Gy and patients with Graves' disease of 37 +/- 37 Gy., Conclusion: Additional application of "cold" iodine after therapy with radioiodine can prolong the effective half life in selected patients. We suspect a correlation with the thyroid iodine pool. This will be the basis for further investigations hopefully resulting in a better patient preselection to determine who might respond to this therapy.

Previous studies have indicated a role of the actin cytoskeleton in the regulation of the cystic fibrosis transmembrane conductance regulator (CFTR) ion channel. However, the exact molecular nature of this regulation is still largely unknown. In this report human epithelial CFTR was expressed in human melanoma cells genetically devoid of the filamin homologue actin-cross-linking protein ABP-280 [ABP(-)]. cAMP stimulation of ABP(-) cells or cells genetically rescued with ABP-280 cDNA [ABP(+)] was without effect on whole cell Cl(-) currents. In ABP(-) cells expressing CFTR, cAMP was also without effect on Cl(-) conductance. In contrast, cAMP induced a 10-fold increase in the diphenylamine-2-carboxylate (DPC)-sensitive whole cell Cl(-) currents of ABP(+)/CFTR(+) cells. Further, in cells expressing both CFTR and a truncated form of ABP-280 unable to cross-link actin filaments, cAMP was also without effect on CFTR activation. Dialysis of ABP-280 or filamin through the patch pipette, however, resulted in a DPC-inhibitable increase in the whole cell currents of ABP(-)/CFTR(+) cells. At the single-channel level, protein kinase A plus ATP activated single Cl(-) channels only in excised patches from ABP(+)/CFTR(+) cells. Furthermore, filamin alone also induced Cl(-) channel activity in excised patches of ABP(-)/CFTR(+) cells. The present data indicate that an organized actin cytoskeleton is required for cAMP-dependent activation of CFTR.

Iodine status was evaluated by assessment of urinary iodine excretion in 221 mothers and their 223 newborns. During the first month after childbirth, 59.3 per cent of the mothers and 26.5 per cent of the newborns received applications of iodized antiseptic containing Polyvidone-iodine. 50.2 per cent of the newborns and 24.9 per cent of the mothers had a urinary iodine of more than 20 micrograms/dl (iodine excess). For the mothers and the newborns who had received applications of iodized antiseptic, 38.2 per cent and 74.6 per cent had an iodine excess, respectively. This iodine excess is directly related to use of iodized antiseptic. Such high iodine levels may contribute to the risk of thyroid disorders, and particularly to transient congenital hypothyroidism at a critical age for normal development of the nervous system.

Iodine deficiency and iodine deficiency disorders are still present in several parts of Europe. Sonography is neither specific in the diagnosis nor sensitive in the evaluation of the amount of autonomous thyroid tissue. Thyroidal autonomy is defined as a functional state of the thyroid and therefore only functional scintigraphic imaging, preferably performed with 99mTc-pertechnetate (99mTcO4-), will offer both high sensitivity and specificity in its diagnosis. Recently the cloning and characterisation of the Na+/I- symporter (NIS) offered a deeper understanding of iodine and pertechnetate uptake in the thyroid gland. Overexpression of the Na+/I- symporter following activation of the adenylate-cyclase-cAMP-cascade has been demonstrated in hot nodules, which gives for the first time an explanation for the enhanced iodine clearance of autonomous thyroidal tissue on a molecular level. The scintigraphic evaluation of thyroidal autonomy is performed both as a quantitative and qualitative thyroid scintigraphy, using a gamma camera fitted with an on-line computer system. A strong and linear correlation between the global 99mTc-pertechnetate thyroid uptake (TCTU) and 123I clearance has been recognised. Therefore TCTU-values can be used as a reliable equivalent of the iodine clearance in the evaluation of actual thyroid function. The clinical value of the TCTU in the diagnosis of thyroidal autonomy is limited because it represents iodine clearance of both normal and autonomous tissue. As a consequence scintigraphic diagnosis and quantification of autonomy can only be established if the global 99mTc-pertechnetate thyroid uptake under suppression (TCTUs) is determined. This method is sensitive in risk stratification of spontaneous or iodine induced hyperthyroidism, in the estimation of the target volume prior to radioiodine therapy independently of its distribution and in the evaluation of therapeutic success after definitive therapy.

In x-ray phototherapy of brain tumours, the tumour is loaded with iodine and exposed to kilovoltage x-rays. Due to the high photoelectric cross sections of iodine, substantial photoelectric interactions occur. The flux of photoelectrons, characteristic x-rays and Auger electrons produce a localized dose enhancement. A modified computed tomography scanner, CTRx, can be used both for tumour localization and delivery of the dose enhancement therapy. Monte Carlo methods were employed to simulate the treatment of iodinated brain tumours with a CTRx. The calculated results reveal the effect of tumour iodine concentration on dose distribution, the degree of skull bone sparing with the application of multiple arcs, and the homogeneity of tumour dose distribution versus iodine concentration. A comparison with 10 MV stereotactic radiosurgery treatment shows the potential of CTRx treatment relative to conventional treatment modalities.

Background: Systemic absorption of iodinated contrast material occurs during endoscopic retrograde cholangiopancreatography (ERCP), the clinical significance of which has not yet been determined., Methods: Urinary iodine excretion was measured before and after coronary angiography (n = 20) and ERCP (n = 12). Thyroid hormone levels were determined before iodine load and after 6 and 24 weeks., Results: Before coronary angiography, iodine excretion was 101 +/- 38.3 micromol/mol creatinine and increased to 865. 10(5) +/- 721. 10(5) micromol/mol on the next day (p

By using the patch-clamp technique we have shown that, in hypotonic extracellular solutions, the mouse neuroblastoma cells Neuro2A (N2A) develop ionic currents mediated by a chloride-selective channel which is also permeable to other anions in accordance with the permeability sequence: I->Br->Cl->gluconate->glutamate-. The currents persist for several hours when Mg-ATP is present in the recording pipette but occur only transiently in the absence of Mg-ATP. Typical blockers of anions channels such as La3+ and Zn2+ do not affect the hypotonicity-activated channel; conversely, the stilbene sulfonate-derivatives, 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), reversibly inhibit the channel in a voltage-dependent manner. Also intact cells exposed to hyposmotic solutions activate volume-regulation mechanisms which decrease the transient volume increase that develops immediately after the application of the hyposmotic challenge. Since N2A neurons have been used as an expression system of exogenous channels, the presence of osmolarity-regulated channels in these cells is an important aspect that deserves the attention of researchers who may wish to express and study the properties of transport proteins in this cell line.

Objective: To observe the effect of testosterone or estradiol on iodine absorption in rat intestine., Method: 50 male adult Wistar rats were divided into 5 groups randomly. 50 females were divided into another 5 groups. Among them, 4 groups were bilaterally testectomized or ovariectomized, 1 group was sham-operated. 7 days after operation, the castrated rats received testosterone (male rats) or estradiol (female rats) at different dosages by intramuscular injection for three days. Then the kinetics of iodine absorption in jejunum and ileum were observed by perfusion in situ. When finished, serum were obtained for detecting TSH, T4 and testosterone or estradiol., Results: In castrated male rats, the value of K12 reduced, K21 increased, K02 reduced, and SP1/2 (the half time of the slow phase) prolonged, implying that the ability of iodine absorption reduced. It reflected that testosterone could promote iodine absorption in intestine in physiological condition. In castrated female rats, the situation was different from that in male rats, the value of K12 increased, K21 reduced, K02 increased, and SP1/2 shortened in jejunum, implying that the ability of iodine absorption increased. It reflected that estradiol could inhibit iodine absorption in intestine in physiological condition. The levels of serum TSH and T4 were not changed significantly in this experiment., Conclusion: In physiological condition, testosterone can promote iodine absorption, while estradiol has the inhibiting effect. The results indicate that gonadol hormone maybe one factor which can influence iodine absorption in intestine. It may explain the phenomenon that the incidence of goiter is different between males and females partly.

The initial water content of a group of 15 pharmaceutically and toxicologically acceptable surfactants showed a tendency to increase with the surfactant hydrophilic-lipophilic balance (HLB) value. Surfactant solubility was determined in chlorine-free "alternative propellants" (n-butane, propane, dimethyl ether [DME], 1,1,1,2-tetrafluoroethane (HFA-134a), and 1,1,1,2,3,3,3-heptafluoropropane [HFA-227ea], and trichloromonofluoromethane [CFC-11] in the absence of cosolvents such as ethanol. Water-soluble surfactants such as Carbowax, Sentry, PEG 300, Tween 20, and Brij 30, with high HLB values showed appreciable solubility in HFA-134a and HFA-227ea. In systems containing > or = 80% propellant by weight, each single-phase propellant-surfactant blend was screened for its ability to solubilize iodine and dissolve or solubilize water with increasing surfactant concentration. This screening was performed to investigate the possibility of formulating high-volatility, single-phase systems with increased polarity and solvency from these conventional excipients and vehicles. Ternary-phase diagrams show the regions of apparent single and multiple phase behavior in each system. Despite the increased polarity of the hydrofluoroalkanes (HFAs), appreciable water solubility was seen only with these surfactants in DME and in the hydrocarbons (HCs) n-butane and propane.

Background: Iodine deficiency is the main cause of endemic goitre. Iodine supplementation and decrease of pituitary TSH are the therapeutical aims. In this study, bioavailability of levothyroxine combined with iodide and the same dose of levothyroxine alone were compared., Patients and Methods: Fourty-eight subjects aged 18 to 40 years were randomly assigned for 6 days either 150 micrograms levothyroxine and 150 micrograms iodide (group A, n = 25) or 150 micrograms levothyroxine (group B, n = 23). Baseline TSH and thyroid hormones were measured 2 days before starting therapy as well as daily till day 6. TRH-test (delta TSH) and thyroid sonography were performed at day -2 and 6., Results: During therapy baseline TSH decreased markedly from 1.26 to 0.35 mU/ml (median) in group A and from 1.37 to 0.39 to 0.39 mU/ml in group B (both p < 0.001), as well as delta TSH (A from 5.66 to 2.61 mU/ml; B from 6.3 to 2.95 mU/ml; p < 0.001). Difference of delta TSH (day -2 versus day 6) was negatively correlated to body surface (r = -0.307; p < 0.05). TT4 levels increased in both groups (A from 7.1 to 9.1 microU/dl; B from 7.2 to 9.4 microU/dl; p < 0.005). No significant differences were noted between both groups for thyroid-related parameters. In both groups, confidence intervals for baseline TSH and TT4 were in the expected range., Conclusion: In this study, similar bioavailability and bioequivalence for levothyroxine and the combination of levothyroxine with iodide were demonstrated.

Mechanisms regulating thyroid hormone synthesis in conditions of proper iodine supply, iodine excess and iodine deficit in subjects with normal thyroid function and in patients with various thyroid gland disorders are presented.

N6-Isopentenyladenosine (i6A), an adenosine and mevalonate derivative, inhibits, like adenosine, TSH-induced cAMP increase and its related events (I- uptake and DNA synthesis) in FRTL-5 cells. This inhibition is dose-dependent and is measurable at 10(-8) M. However, unlike adenosine, i6A prevents TSH-promoted microfilament disassembly. The effect of i6A on cytoskeletal structure is antagonized by pertussis toxin and could be assigned to its N6 substitution since it can be mimicked by other synthetic N6-adenosine derivatives. It is suggested that a step beyond cAMP is involved, since i6A prevents also microfilament disassembly induced by 8-bromo-cAMP. This is the first demonstration that an adenosine derivative, which is also an end-product of the isoprenoid pathway, affects cAMP-dependent microfilament organization.

Povidone-iodine solution is widely used to disinfect the skin surface or prevent suppuration during human and animal surgery. Using radioisotope 125I, we examined whether iodine may be absorbed and then concentrated in the thyroid gland when povidone-iodine solution is applied to the skin of rats or mice. The competition for 125I uptake was examined in mice and rats after the application of povidone iodine to the skin. We also traced the process of absorbed 125I in the thyroid glad during the fixation for tissue preparations. Povidone-iodine applied to the skin significantly reduced the uptake of 125I both in mice and rats. Significant flux of 125I from the thyroid gland in povidone-iodine treated animals was noted during the thyroid fixation of tissue preparations. From these results, povidone-iodine application to the skin instead of stable KI administration may be practical for preventing the uptake of 125I by the thyroid gland during 125I compound administration for medical therapy. In animal experiments concerning thyroid functions, careful attention must be paid when povidone-iodine is used for disinfection in animal surgery.

The contents of bromine and iodine in samples of heart, liver, spleen, lung, muscle, and hair from healthy adults living in Beijing, China, were determined using epithermal neutron activation analysis. The results indicate that the contents of bromine in lung and iodine in liver are higher than those in other tissues, except human hair. The bromine contents in Beijing human tissues are significantly lower than those in other countries. The contents of iodine are slightly lower than those in other countries, but the difference is not significant. Three biological standard reference materials were simultaneously determined with the samples, and our results agree well with the certified values.