Thyroid-related Hormones Research Articles

Optic nerve sheath meningioma: a case report

A case of a 75-year old male with right-sided exopthalmos is presented. Outside proptosis of the right eye was initially observed 6 years ago. Opthalmological and endocrinological clinical examination as well as laboratory tests revealed no pathology from optic nerve disc, optic bulb and thyroid related hormones. MRI study demonstrated an optic nerve meningioma. The key imaging findings and the differential diagnosis were discussed in this present paper.

Effects of developmental hypothyroidism induced by maternal administration of methimazole or propylthiouracil on the immune system of rats

Methimazole (MMI) and propylthiouracil (PTU) are popularly used antithyroid drugs (ATDs) for the treatment of Graves' hyperthyroidism. The aim of the present study was to determine the effects of ATDs on the developing immune system of the rats.Maternal Sprague–Dawley rats were given drinking water containing 200 ppm of MMI, 12 ppm of PTU (high-dose PTU), or 3 ppm of PTU (low-dose PTU) between gestational day (GD) 10 and postnatal week (PNW) 3. Exposure to the ATDs was ceased upon weaning at PNW3, and the male offspring were sampled at PNWs 3 or 11. The serum thyroid-related hormone levels and the hematological components in the offspring were then determined. The expressions of surface markers in the spleen, thymus and peripheral blood were determined using flowcytometry. The weights of the body, spleen and thymus and the splenic and thymic cell numbers were decreased in the MMI-treated and the high-dose PTU-treated animals at PNWs 3 and 11. The serum levels of thyroid-related hormones were depressed in the MMI and high-dose PTU groups. FACS analysis revealed that the ATDs caused proportional changes in the lymphoid cell subpopulations. The proportion of B cells among the total lymphocytes was significantly decreased at PNW3, whereas that of T cells, especially of inactive T cells, was dramatically increased. Moreover, the proportion of CD4+CD25+ regulatory T cells was significantly increased in the spleen and peripheral blood at PNW3. Most of the above-described changes had recovered to normal levels at PNW11. These results suggest that ATDs might have temporal immunomodulatory effects on the developing immune system.

The Association Between Urinary Monoester Phthalates and Thyroid Hormone in Pregnant Women

TM1-O-09 This study is aimed to investigate the association between phthalates exposure and thyroid hormones in pregnant women. Twenty-eight second-trimester pregnant women were recruited from our hospital. The single spot urine and blood samples were collected for the determination of 5 monoester phthalates by LC/MS/MS and thyroid related hormones, respectively, after signing a consent form. Information obtained from the questionnaire included demographic characteristics and phthalates exposure (cosmetic use, frequency of dietary intake, and consumer plastic products usage). Median levels of 5 urinary phthalate metabolites, including monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBuP), monobenzyl phthalate (MBzP), mono-2-ethylhexyl phthalate (MEHP), were as follows: MBuP (92.3 ppb), MEP (31.6 ppb), MEHP (24 ppb), MMP (5.4 ppb), and MBzP (0.9 ppb). MBuP (100%), MEHP (100%) and MEP (96.5%) were detected from most of the samples, but MMP and MBzP were identified only in 46.4% and 21.4% samples, respectively. No associations were found between the levels of 5 urinary monoester phthalates and demographic characteristics (age, BMI, and others). The MBuP and MEHP levels in urine samples from pregnant women in Taiwan were 6 and 20 times higher than those in Americans. Significant negative correlation between the levels of MBuP and T3 and Free T4 (T3: R2 = 0.177, P = 0.033; FT4: R2 = 0.231, P = 0.013) were found, respectively, indicated the probable anti-thyroid effect in pregnant women during the second trimester. After correction of urinary creatinine, the median levels were as follows: MBuP-c (346.4 μg/g creatinine), MEP-c (123.1 μg/g creatinine), MEHP-c (86.2 μg/g creatinine), MMP-c (13.1 μg/g creatinine), and MBzP-c (3.1 μg/g creatinine). Significant correlation between the level of urinary MBuP-c and MEHP-c in pregnant women were found and showed that the exposure sources of DBP may be similar to DEHP (R2 = 0.687, P < 0.01). All samples were separated into high- and low-level groups by median levels of adjusted-urinary monoester phthalates. The consumption of ruminants in high MEHP level group and the use of personal care products in high MEP level group were significant higher than the low-level group, respectively. Estimated daily intake dose (DIest) of 5 phthalates in pregnant women were calculated from the level of urinary monoester phthalates based on the pharmacokinetics model of PAEs. The calculated median DIest of 5 phthalates in pregnant women were 9.28 μg/kg per day (DBP), 5.17 μg/kg per day (DEHP), 3.01 μg/kg per day (DEP), 0.3 μg/kg per day (DMP) and <0.1 μg/kg per day (BBP). The calculated median DIest of DBP and DEHP of pregnant women in Taiwan were 5 and 7 times higher than those in Americans.

Determination of intrathyroidal iodine by X‐ray fluorescence analysis in 60‐ to 65‐year olds living in an iodine‐sufficient area

X-ray fluorescence (XRF) is a non-invasive method for determining the iodine content of the thyroid gland in vivo. In spite of the obvious clinical value of such a method in situations of iodine deficiency or iodine overload, the method has not so far been widely used. The objective was to investigate the applicability of the XRF method in a larger number of subjects. The study comprised 37 individuals, aged 60-65 years, who had spent their entire life with iodine supplementation through iodinated table salt. Individuals with (previous) thyroid disease were excluded. The individual thyroid function had previously been evaluated by measurements of thyroid-related hormones, thyroid volume and 131-Iodine (131I) uptake which indicated a sufficient iodine intake of the population in the area. Iodine in the right thyroid lobe in each subject was examined using XRF. The mean thyroid iodine concentration was 0.4 mg mL(-1), corresponding to a mean total iodine content of 5.2 mg (range 0.9-20.2). There was a pronounced difference between individuals. No correlation was found between iodine concentration and 131I uptake or thyroid volume. Neither was iodine content and 131I uptake correlated. In a population living under iodine-sufficient conditions, a large variation of iodine stored in the thyroid is compatible with euthyroidism. Determination of the iodine pool by XRF investigation is feasible in a clinical setting and the method offers a unique possibility to study the intrathyroidal iodine pool in subjects with thyroid disease. The low radiation dose enables the use of the method in pregnant women and also in young individuals.

Níveis de hormônios tireoideanos em pacientes com dissecção aórtica: comparação com controles e correlação com a porcentagem de área da camada média composta por depósitos mixóides

Deposits of myxoid material, similar to myxedema related to thyroid disease, are described in the medial layer of aortas with dissection. We analyzed the clinical or subclinical thyroid dysfunction of patients with this disease and analyzed whether a correlation exists between serum levels of thyroid-related hormones and the myxoid content of the aortic media. We measured, with standard methods, serum levels of triiodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH) in 28 patients who underwent aortic dissection and free T4 in 20 of them. The same hormones were quantified in 20 control patients matched by sex and age. Results were compared by using the Mann-Whitney test. We also measured the percentage of the aortic media occupied by myxoid material in the surgical specimens of 25 of the patients with aortic dissection and analyzed its correlation with hormone levels by using the Pearson test. In the 20 pairs in which the amount of hormones was compared, the mean values for T3, T4, free T4, and TSH were 1.22ng/mL, 9.89mcg/dL, 1.18ng/dL, and 5.45 microIU/mL in study patients and 1.15ng/mL, 8.57mcg/dL, 1.32ng/dL, and 2.15 microIU/mL in controls. Neither these differences nor the correlation between the percentage of myxoid content (mean=30%) and the values for T3, T4, free T4, and TSH (mean 1.22ng/mL, 9.44mcg/dL, 1.20ng/dL, and 5.08 microIU/mL, respectively; n= 25) were significant. Our data suggest that serum levels of thyroid hormones have no relation with the myxoid content in the aortic media in cases of aortic dissection.

Eating behavior and thyroid disease in female obese patients

It has been suggested that preexisting thyroid disease (TD) could be a risk factor for the development of eating disorders. The aim of this study was to compare eating attitudes and behavior in female obese patients with and without TD. Thyrotropin (TSH) was determined in 256 patients aged 44.9±14.7 years with body mass index (BMI) >30 kg/m 2; eating attitudes and behavior were assessed with the Eating Disorder Examination (EDE). EDE Shape Concern score was significantly higher in patients with previous or current hypothyroidism ( N=30) than in the rest of the sample. Among patients without known TD, no difference in eating attitudes was observed between patients with elevated TSH ( N=24; 11%) and those with normal thyroid function. The prevalence of binge eating disorder (BED) in the total sample was 9.7%; no difference in prevalence was observed between patients with and without a history of hypothyroidism, and between those with and without previously unknown hypothyroidism. In conclusion, known hypothyroidism is associated with increased shape concern; this does not appear to be related to differences in current levels of thyroid hormones or related hormones.

Thyroid function and anti-thyroid antibodies in MS patients screened for interferon treatment. A multicenter study

Interferon beta (IFNB) treatment for multiple sclerosis (MS) has been associated with thyroid disorders (TD), in particular in patients with subclinical TD or anti-thyroid (AT) autoantibodies (autoAb) before starting treatment. TD and AT autoAb frequency was reported increased in MS. To determine whether MS patients have subclinical thyroid function abnormalities or anti-thyroid autoimmunity predisposing to develop TD, we performed a prospective multicenter screening of thyroid function and autoimmunity in 152 relapsing–remitting (RR) MS patients selected to receive IFNB treatment and in 437 healthy normothyroidal controls. Thyroid-related hormones and anti-thyroid microsomal antigen (anti-TMA) autoAb were tested with sensitive immunoradiometric or chromatographic assays. Cases were stratified for different progressively decreasing or increasing cutoff values of thyroid-stimulating hormone (TSH) (0.3, 0.2, 0.1, 3 and 5 mIU/l), and odds ratios (OR) with 95% confidence intervals (CI) calculated using logistic regression adjusted for gender, age, and anti-TMA autoAb positivity. The frequency of cases below or above the TSH cutoff values was not significantly different in MS patients and controls, and the risk to have an abnormal TSH level was not significantly increased in MS patients (OR ranging 0.37–0.84; CI, 0.05–3.01), even if anti-TMA autoAb positive (OR ranging 0.35–0.85; CI, 0.04–3.00). Frequencies of subclinical hypothyroidism and of anti-TMA autoAb positivity were, however, trending higher in MS men (ranging 5–7%) than in controls (3%). MS patients do not have an increased risk of subtle thyroid function abnormalities, subclinical TD, or anti-TMA autoAb positivity that may predispose to develop thyroid dysfunction during IFNB treatment. The positive trend for subclinical hypothyroidism and anti-TMA autoAb positivity, however, advises a longitudinal study of thyroid function and autoimmunity during IFNB treatment to see whether patients with baseline subclinical thyroid dysfunction develop clinically significant alteration during treatment.

Biological characteristics and chemosensitivity profile of four human anaplastic thyroid carcinoma cell lines

Anaplastic thyroid carcinoma is a rapidly growing, aggressive neoplasm affecting the elderly which does not respond to most of the therapies. We established cultured cell lines from four untreated tumors. The cultures grew in a monolayer of spindle-shaped cells in three cell lines and of small polygonal cells in one line, having relatively long doubling times and chromosomal abnormalities. The xenotransplantation of the lines in athymic nude mice produced tumors with a histology similar to the original tumors. The immunocytochemical staining showed the expression of PCNA, HLA-class 1, cytokeratin , vimentin and FAS (fatty acid synthase) but not CEA, desmin or P-glycoprotein. The lines secreted TPA, IL-6, IL-8 and few or no thyroid-related hormones in the culture supernatant. One cell line produced G-CSF. The chemosensitivity assay revealed intrinsic drug resistance to nine out of 11 antineoplastic agents. The reverse transcriptase-polymerase chain reaction (RT-PCR) detected MRP (multidrug resistance-associated protein) mRNA but not mdr (multidrug resistance protein)-1 and mdr-3 mRNAs. This finding indicates that the multidrug resistance of these lines is mediated by a P-glycoprotein-unrelated mechanism. The RT-PCR also presented FAS mRNA in all the lines, and IL-6 and IL-8 mRNAs in some of the lines.

Promoting effects of xylazine on development of thyroid tumors in rats initiated with N-bis(2-hydroxypropyl)nitrosamine and the mechanism of action.

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.

Modifying Effects of Endocrine Disrupting Chemicals on N-bis(2-hydroxypropyl) Nitrosamine and Sulfadimethoxine-Induced Thyroid Carcinogenesis in Rats.

To clarify whether 17β-estradiol 3-benzoate (EB), methoxychlor (MXC), atrazine (ATR), or bisphenol A (BPA) have any modifying effects on relatively late stages of thyroid carcinogenesis, six-week old female castrated F344 rats in Experiments 1 and 2 first received a single subcutaneous injection of 2000 mg/kg body wt of N-bis (2-hydroxypropyl) nitrosamine (DHPN) and, starting one week later, were given drinking water containing 1000 ppm sulfadimethoxine (SDM) for 8 weeks. Then, in Experiment 1, cholesterol pellets containing 0.5 mg EB were subcutaneously embedded and renewed every 4 weeks for 25 weeks. Controls received basal diet alone. In Experiment 2, rats of the control, MXC, ATR, or BPA group received diet containing no supplement, 1000 ppm MXC, 400 ppm ATR, and 10000 ppm BPA, respectively, for 27 weeks. Thyroid follicular cell hyperplasias, adenomas, and/or carcinomas were induced in all of the groups. In Experiment 1, the incidence of adenomas in the EB group was significantly increased, as compared to the corresponding control group value. In Experiment 2, the incidences of carcinomas in the MXC and BPA groups were significantly lower than in the corresponding control group. Serum estrogen levels and the PCNA labeling index for carcinomas in the EB group were significantly elevated but there was no clear alteration in serum thyroid related hormone levels. Serum T3 levels in the MXC and ATR groups were significantly reduced, whereas serum T4 was increased in these as well as the BPA group. No significant fluctuation in serum TSH levels was observed in these treated groups. The results of the present studies suggest that EB with strong estrogenic activity, but not MXC and BPA with only weak estrogenic activity or ATR, exerts promoting effects on thyroid carcinogenesis in rats.

Immunologic and Biochemical Factors in Hyperemesis gravidarumwith or wit hout Hyperthyroxinemia

Objective: This study was set up to investigate the relationship between immune process and high levels of human chorionic gonadotropin-β (βhCG) in hyperemesis patients with or without hyperthyroxinemia. Methods: βhCG, immune parameters and thyroid related hormones were assayed in hyperemesis patients and in controls. Results: Mean serum βhCG, fT₄ and TSH levels were significantly higher in hyperemesis patients than in controls (p < 0.01, p < 0.01, p < 0.05, respectively). Further, immune parameters regarding IgG, IgM, C₃, C₄ and lymphocyte count were significantly higher in patients than in controls (p < 0.05, p < 0.01, p < 0.01, p < 0.05, p < 0.01, respectively). In hyperemesis patients with hyperthyroxinemia, mean serum βhCG, IgG and IgM were significantly higher than in hyperemesis women without hyperthyroxinemia (p < 0.001, p< 0.05, p < 0.05, respectively). βhCG was positively correlated with fT₄ (r = 0.45, p < 0.05), with lymphocyte count (r = 0.47, p < 0.01), with IgM (r = 0.38, p < 0.05) and with C₃ (r = 0.40, p < 0.05) in hyperemesis patients. A negative correlation between βhCG and TSH (r = –0.43, p < 0.05) was noted in the hyperemesis group. Free T₄ showed a positive association to IgM (r = 0.49, p < 0.01), to IgG (r = 0.40, p < 0.05), to lymphocyte count (r = 0.45, p < 0.05). Conclusion: Immunologic activity in pregnancy may have an effect or role on the stimulatory mechanism of βhCG in hyperemesis patients with or without hyperthyroxinemia.

Inhibition of thyroid iodine uptake and organification in rats treated with kojic acid.

In order to elucidate the mechanisms of reduction of serum thyroid hormones caused by continuous administration of kojic acid (KA) and its thyroid tumor-promotion effects, male F344 rats were given pulverized basal diet containing 0.008%, 0.03%, 0.125%, 0.5%, or 2% KA for 4 weeks. As an untreated control group, additional rats were given basal diet alone for the same period. The thyroid 125I uptake was significantly decreased in the groups receiving 0.03% or more. In addition, significant reduction of organic formation of iodine and serum T3 and T4 levels were observed in the 2% KA group along with pronounced elevation of serum (TSH). Both absolute and relative thyroid weights were significantly increased in the groups receiving 0.5% of KA or more. Histopathologically, decreased colloid in the thyroid follicles and follicular cell hypertrophy in the thyroid were apparent at high incidences in the groups given 0.03% or more. In addition, thyroid capsular fibrosis was evident in all rats of the 2% KA group. In quantitative morphometrical analysis, the ratio of the area of follicular epithelial cells to the area of colloids was significantly increased in the groups given 0.03% KA or more. The results suggest that KA alteration of thyroid-related hormone levels in the 2% KA group are due to inhibition of iodide uptake and iodine organification in the thyroid, with tumor-promoting effects on development of thyroid proliferative lesions, probably secondary to prolonged serum TSH stimulation resulting from negative feedback through the pituitary-thyroid axis.

Randomized, Double Blind, Placebo-Controlled Trial of Low Dose Iodide in Endemic Goiter

Iodine (I) is essential for normal thyroid function, and the majority of subjects tolerate a wide range of dietary levels. However, a subset of individuals upon exposure to normal or elevated levels of I develop thyroid dysfunction and autoimmunity. In this double blind trial, we evaluated efficacy and tolerability of low dose I in adults with euthyroid, diffuse, endemic goiter. Sixty-two subjects were randomly assigned I (0.2 mg/day) or placebo for 12 months. After termination of therapy, both groups were followed for a further 6 months. Thyroid sonography and determinations of thyroid-related hormones, urinary I excretion per 24 h, and thyroid antibodies were carried out at baseline and at 3, 6, 9, 12, 15, and 18 months. Markedly elevated urinary I values were found during therapy in subjects receiving I (32 at baseline vs. 213 micrograms/24 h at 12 months; P = 0.0001) compared to placebo (34 and 33 micrograms/24 h, respectively; P < 0.0001 vs. I). I substantially reduced thyroid volume (29 vs. 18 mL at 12 months; -38%; P = 0.0001), and at 18 months, the therapeutic effect was sustained. In the placebo group, no significant changes were observed. High microsomal and thyroglobulin autoantibody titers were present in 3 of 31 (9.7%) subjects receiving I, and I-induced hypo- and hyperthyroidism developed in 2 and 1, respectively. Fine needle biopsy revealed marked lymphocytic infiltration in all 3 cases. After withdrawal of I, thyroid dysfunctions spontaneously remitted, and antibody titers as well as lymphocytic infiltration decreased markedly. Follow-up of these 3 subjects for an additional 2 yr showed normalization of antibody titers in 2. Thus, among subjects with endemic goiter, low dose I successfully normalized thyroid volume and body I supplementation; nevertheless, reversible I-induced thyroid dysfunctions and autoimmunity were observed in nearly 10% of the subjects.

Control of Iodine Deficiency Using Iodination of Water in a Goitre Endemic Area

Salt iodination is the method of choice for prevention of iodine deficiency in most parts of the world. However, establishment of such a program frequently involves considerable changes in the marketing and distribution patterns and requires years to achieve. This study was conducted to evaluate the efficiency of using well-defined water sources containing iodine-saturated silicon matrices for providing adequate iodine supply to an iodine deficient population in Kordofan State, Western Sudan. A system of water iodination using silicon matrices containing 30% sodium iodide placed in polyethylene baskets was used in four villages using either traditional wells or hand pumps. Before and every 6 months after iodination of water, urine and blood samples were obtained for determination of iodine and thyroid-related hormones, respectively. Goitre assessment on the village populations were performed at the start and 2 years later. Improvements in iodine status were recorded in all the study villages. The water iodine concentrations increased and a higher iodine content was observed in the hand pumps compared to the traditional wells. The median urinary iodine concentrations increased significantly, from 0.19, 0.20, 0.19, 0.11 to 1.20, 1.10, 0.37, 0.30 μmol/l in the four villages, respectively. The percentages of subjects with serum TSH above 4 mU/l were decreased from more than 30% before iodination to less than 15% at 2 years after iodine supply and the mean serum thyroxine hormone values rose. The rates of goitre decreased from 69% to less than 25%. The study shows that this system is effective, cheap, safe and practically applicable under conditions prevailing in rural areas in developing countries with iodine deficiency.

Preparation of magnetic particle antibodies for radioimmunoassay and immunoradiometric assay of thyroid related hormones

Silanized magnetic particles have been developed by means of a number of different methods for coupling antibodies for use in radioimmunoassay (RIA) and immunoradiometric assay (IRMA) of thyroid related hormones. Carbodiimide, glutaraldehyde, glutaric anhydride and spacer-arms coupling methods were studied for immobilization of triiodothyronine (Ts), thyroxine (T4) and thyroid stimulating hormone (TSH) antibodies on magnetic particles respectively. The effect of the magnetic particle preparation on the couplings was discussed. The influence of coupling conditions on the preparation of magnetic particle antibodies and the assay performance was also investigated. The storage stability and reproducibility of the magnetic particle T3, T4 and TSH antibodies were good enough for use in total T3, total T4 RIA and TSH IRMA. A comparison of five types of magnetic particles from different sources for coupling TSH antibody for TSH IRMA application was made. Silanized magnetic particles and other types of particles showed comparable results. Five TSH antibodies, including two polyclonal and three monoclonal antibodies coupled to silanized magnetic particles respectively, were used in TSH IRMA. It was found that each of them and a commercial monoclonal TSH antibody as label formed good sandwich partners and gave a high signal to low levels of TSH.

Effect of thyroid stimulating hormone on the development and progression of rat thyroid follicular cell tumors.

Time course changes in cell proliferative activity of thyroid focal hyperplastic and tumorous lesions as well as blood thyroid-related hormones in male F344 rats initiated with N-bis(2-hydroxypropyl)nitrosamine (DHPN: 2800 mg/kg body weight, single s.c. injection) were examined following chronic administration of 0.1% sulfadimethoxine (SM) in the drinking water for 1, 4, 8, 12 and 16 weeks and at the end of a subsequent 4-week recovery period. Serum thyroid stimulating hormone (TSH) levels increased rapidly from week 1 of SM treatment, reaching a peak at week 8, and then decreased gradually with prolongation of treatment period, although remaining significantly elevated as compared with the corresponding controls at all time points up to week 16. Follicular cell hyperplasias and adenomas of the thyroid occurred from week 4 and carcinomas from week 8. All of these lesions showed high cell proliferative activities corresponding to high serum TSH levels during the early stage, but the levels in hyperplasias and adenomas decreased rapidly with prolongation of SM treatment. After the recovery period, serum TSH levels had returned to below the normal range and cell proliferation in follicular hyperplasias and adenomas had stopped or was very low. Some carcinomas demonstrating invasive growth also showed remarkable decreases in the cell proliferative activity. The results of our study strongly suggest that a high serum TSH level plays an important role in the early stage of thyroid tumorigenesis and that some tumors exhibiting invasive growth are still dependent on TSH stimulation.

FD&C Red No. 105 (Rose Bengal B) neutralizes the thyroid tumor promoting effect of iodine-deficient diet in rats

The effect of 3,4,5,6-tetrachloro-2′,4′,5′,7′-tetraiodo-fluorescein sodium salt (Rose Bengal B or FD&C Red No.105, molecular weight 1017.6) on the thyroid of rats treated with N-bis(2-hydroxypropyl)-nitrosamine (DHPN) and iodine-deficient (I-def) diet is studied. Six-week-old male F344 rats were divided into seven groups (20 each) and given a single subcutaneous injection of DHPN (2800 mg/kg body wt). From week 2 to 20, I-def diet was given in combination with either FR105 (1.25, 5.0, or 20 mg/1) or potassium iodide (KI, 12.5, 50.0 or 200 μg/1) in drinking water. As a result, an amount of 1.25 mg/1 of FR105 was slightly more effective than 200 μg/1 of KI in terms of inhibition of the effect of I-def diet on thyroid weight, morphology, thyroid-related hormones and thyroid tumor development. It was calculated that 1 μmol/1 of FR105 was slightly more potent than 1 μmol/1 of iodide ion. As each FR105 molecule has four iodide residues, at least 25% of total iodide residues were calculated to be utilized by the rats given I-def diet.

The effects of different doses of oral iodized oil on goiter size, urinary iodine, and thyroid-related hormones.

The prevention of iodine deficiency is still a worldwide concern. This study, conducted in Soja in western Sudan, was carried out to evaluate the effects of a dose of iodized oil sufficient enough to give maximum protection against goiter and provide an acceptable iodine supply without side-effects over a sufficiently long period of time. Adult goitrous subjects (n = 117) were randomly assigned to three groups, A, B, and C, and received a single oral dose of 200, 400, or 800 mg iodine, respectively. Urine and blood samples were collected at the start of the study and monitored for 1 yr. In the 3 groups, mean serum T4 and median urinary iodine and serum TSH values were restored to reference limits, and these were maintained for about 1 yr. In each treatment group, about two thirds of the subjects displayed a reduction in goiter size, and the 400- and 800-mg doses were not more efficient than the 200-mg dose to accomplish normalization of thyroid hormone values. A temporary rise in TSH was noted 1 week after iodine administration in 1, 3, and 10 subjects, respectively, and 1, 0, and 3 subjects showed biochemical signs of thyrotoxicosis during the year after treatment with the 3 different doses. The data indicate that oral administration of 200 mg iodine is effective and acceptable for treating iodine deficiency in adults for 1 yr. Because of the risks of side-effects and the shortage of medical resources, higher doses are not recommended.

The effects of different doses of oral iodized oil on goiter size, urinary iodine, and thyroid-related hormones

The effects of different doses of oral iodized oil on goiter size, urinary iodine, and thyroid-related hormones

External quality assessment for the RIA of thyroid related hormones: Second phase

An external quality assessment was conducted to assess the performance of various laboratories for RIA of thhyroid related hormones in two phases. In the first phase thirty five laboratories participated. At the end of first phase a meeting cum workshop was organised to discuss the results of first phase, difficultires faced by the participants and pinpoint the short oming. A second phase was then initiated with an objective of improvement in the performance, if any, where twelve samples from four pools were distributed to twenty four laboratories who participated for the second phase. The overall return of the results increased significantly from 71.8% (1586/2208) for the first phase to 92.4% (732/792) for the second phase. The inter laboratory %CV for T3, T4 and TSH were lower during the second phase (30.6%, 19.0% and 31.6% respectively) as compared to those observed during first phase (36.3%, 22.7% and 52.8% respectively). Similarly, there was an improvement in reproducibility of ALTM as %CV for T3, T4 and TSH decreased from 6.0%, 9.8% and 13.4% respectively to 4.5%, 4.6% and 8.5% respectively. The individual performances of the participating laboratories viz. bias, variability of bias and imprecision also showed a trend towards improvement as percent laboratories having desirable or acceptable results for T3, T4 and TSH increased from 10.7%, 60.7% and 0.0% respectively to 20.8%, 66.7% and 22.2% respectively. External quality assessment thus appears to be beneficial in assessing the performane of a laboratory in comfparison with other laboratories and indeed helps in improving the performance.