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Objective:To follow up and observe the intellectual development of school children aged 8 to 10 in Baicheng County, Xinjiang Uygur Autonomous Region, which was a severe iodine deficiency disorders region in history, before and after effective control of the disease, in order to evaluate the impact of iodine supplementation on protection of children's intellectual development and provide a theoretical basis for scientific supplements of iodine.Methods:From 1989 to 2018, Combined Raven's Test for Rural in China (CRT-RC) was used to observe the intellectual development status of 660 Uyghur school children aged 8 to 10 in Baicheng County in 1989, 2002, 2006, 2012 and 2018, respectively. Children's intelligence quotient (IQ) was calculated using CRT-RC's 1987 normal sample of rural children in the same age group; the data of average iodized salt coverage rate (C-IS) and childhood goiter rate (GR) from multiple local surveys and the median urinary iodine (MUIC) of children were collected, combined with the "Criteria for Elimination of Iodine Deficiency Disorders" (GB 16006-2008) and the United Nations International Children's Emergency Fund (UNICEF) recommended standards, the status of iodine deficiency during children's growth (IDG) was divided into complete exposure to iodine deficiency, no exposure, and semi-exposed. The Flynn effect (FE) gain was calculated using norm samples of children aged 8 to 10 in 1987, 1996 and 2006 of CRT-RC, and the differences in children's intellectual development after FE correction before and after IDG reached the standard were compared.Results:The IQ of children were (81.67 ± 14.13), (83.26 ± 14.05), (89.68 ± 13.58), (98.50 ± 14.33) and (103.23 ± 15.25) points in Baicheng County in 1989, 2002, 2006, 2012 and 2018, respectively, the difference between different years was statistically significant ( F = 58.357, P < 0.01). The three indicators of C-IS, GR, and MUIC didn't meet the standards during the IDG evaluation period in the 1989, 2002, and 2006 groups, which were the complete exposure to iodine deficiency; in the 2012 group, only the MUIC met the standard, which was semi-exposed; in the 2018 group, three indicators all met the standard, which was no exposure. The FE gains of 1987 with 1996, 1996 with 2006 were 0.96 points/year and 0.74 points/year, respectively; after FE correction, the actual gains of IQ of 2002 and 2006 compared with 1989, 2012 and 2018 compared with 2006 were - 9.57, - 6.11, 4.38, and 4.67 points, respectively. Conclusions:In iodine deficiency areas, intermittent iodine supplementation (1989 - 2009) for children exposed to iodine deficiency during growth still cannot effectively protect children's intellectual development; continuous and effective iodine supplementation (2010 - 2018) with iodized salt as the core and covering children's growth period has obvious positive effects on protection of children's normal intellectual development. In the future, we will continue to observe the influence of IDG full-cycle suitable iodine nutrition on children's intellectual development.
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In response to the recent interest in potassium iodate iodized (KIO 3) salt safety, we reviewed the background of KIO 3 in replacing of potassium iodine (KI) as salt fortificator and its effect in prevention and control of iodine deficiency disorders (IDD) or endemic goiter, the decision-making changes of fortificator of iodized salt in China, the research and progress of toxicology, and whether IO 3- exits in urine without decomposition or not. Our inclusions are: it is believed that the decision of the international organizations and agencies of national and local governments about the safety of KIO 3 in iodized salt is supported by adequate and scientific evidents. When it comes to the safety of KIO 3 added in iodized salt, it must be based on the trace amount of KIO 3 in salt which is limited while intaking. Reductive substances in food, cooking heating or reduction system of human body might quickly reduce trace IO 3- to I -, therefore, IO 3- might not be found in fresh urine.
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Objective To observe and compare the different orthotopic models of papillary thyroid cancer ( PTC) cell lines of RET/PTC1 rearrangement and BRAFV600E mutation in nude mice. Methods Human PTC cell lines TPC-1, BHP5-16 and BHP2-7 were used. The genotypes of RET/PTC1 rearrangement and BRAFV600E mutation were determined by realtime-PCR and DNA sequencing analysis. The cells(2×105) were injected into the thyroid gland of nude mice. The nude mice were executed at 4th, 12th week, and then their thyroid tumors were removed and weighed. The levels of thyroid hormone were detected using chemiluminescent immunoassay. Results Both TPC-1 and BHP2-7 cells were identified as RET/PTC1 rearrangement by real time-PCR, and the expression of RET/PTC1 rearrangement in BHP2-7 cell was higher than that of TPC-1 cell. BRAFV600E mutation was found in BHP5-16 cell by DNA sequencing analysis, but was not found in TPC-1 and BHP2-7 cells. There were different characteristics in three orthotopic nude model groups. Tumorigenic rates of TPC-1 and BHP5-16 groups were 100%, but the growth of tumor was more rapid in BHP5-16 group than that in TPC-1 group, with more weight tumor. The changes of thyroid hormone levels in BHP5-16 group and TPC-1 group were the same, which were normal at 4th week and sharply decreased at 12 th week(P0. 05). Conclusions It showed difference in the orthotopic models of PTC cell lines of RET/PTC1 rearrangement and BRAFV600E mutation in nude mice. BRAFV600E mutation has obvious impacts on increasing tumorigenic rate and promotion of tumor growth in the orthotopic model. It should not be ignored that advanced thyroid tumor will lead to the destruction of thyroid function.
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Objective To observe the effects of different iodine intake on the thyroid tumor growth and thyroid function in the orthotopic nude mice model of human papillary thyroid carcinoma (PTC) cell line TPC-1.Methods Human PTC cell line TPC-1 (2 × 105) was injected into the left thyroid gland of nude mice.After the operation,the nude mice were randomly divided into three groups:low iodine group (LI),normal iodine group (NI),and high iodine group(HI,50 folds of normal iodine) based on the iodine levels contained in their diet.4 and 12 weeks later,the nude mice were executed,then their thyroid tumors were removed and weighted.The levels of urinary iodine were measured with As3+-Ce4+ catalytic spectrophotometry using ammonium persulfate digestion method.The thyroid hormone level was detected using chemiluminescent immunoassay.The morphology and structure of thyroid tumor tissue was observed by microscope.Results The iodine intervention feeding was successful according to urinary iodine level of LI,NI,and HI groups,paralleled to their iodine intakes.However,the difference of the weight of thyroid tumor in three groups had no statistical significance(P＞0.05).At 4 weeks,compared with control group,the levels of thyroid hormones were normal in NI group,while lower T4 and normal T3 were found in LI group.However,T4 was higher and T3 was lower in HI group (P＜0.05).At 12 weeks,the levels of thyroid hormones all were decreased due to the enlargement of thyroid gland tumor in NI,LI and HI groups.T4 and T3 in LI group were the lowest among three groups,even T4 was below detection limit.T4 was normal and T3 was lower in HI group as compared to control group.Conclusion Iodine intake may not significantly affect tumor growth in the orthotopic nude mice model of human PTC cell line TPC-1,but it has a significant effect on the synthesis of thyroid hormones.
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Objective To observe the implementation of national food safety standard for “Iodine Concentration in Edible Salt”(GB 26878-2011) and its effectiveness on iodine nutritional status of key populations. Methods Information of iodine concentration in edible iodized salt of various provinces (autonomous regions and municipalities, including Xinjiang Production and Construction Corps) was collected using Baidu Searching Engine through the establishment of key words. Sal t samples were collected in Tianjin City and Aksu Region of Xinjiang , and the salt iodine concentration in both places was 30 mg/kg. In Tianjin, Hongqiao, Tanggu and Hangu, Beichen were selected as representatives of the downtown areas, the coastal areas and the suburbs, respectively and counties of Baodi and Ji were iodine deficiency areas in history. Sampling work was carried out from August 2012 to March 2013 in Tianjin. In Aksu, Yatuoer Township and Charqi Town in Baicheng County, Aotebeixi and Aketuohai Townships in Wushen County were chosen as iodine deficiency areas, and the survey was carried out from January to September 2013 . Random urine samples of school-age children ( 8 - 10 years old ) , pregnant women and lactating women were collected; urinary iodine was measured following the Method for Determination of Iodine in Urine by As3+-Ce4+ Catalytic Spectrophotometry(WS/T 107-2006) and iodine in edible iodized salt was measured following the General Test Method in Salt Industry Determination of Iodideion ( GB/T 13025 . 7-1999 ) . Results Fourteen of the provinces(autonomous regions and municipalities, including the Corps of Xinjiang) chose 25 mg/kg as their iodine concentration in edible iodized salt and 13 provinces chose 30 mg/kg. Besides, there were another 5 provinces providing 30 mg/kg particularly for pregnant women and lactating women while 25 mg/kg for other populations. In Tianjin, the medians of iodine concentration in edible iodized salt were ranged from 24.4 - 32.1 mg/kg in retail stores and 26.4 mg/kg at households. The household coverage rate of iodized salt and the proportion of households using adequately iodized salt were 78.5%(168/214) and 62.6%(134/214), respectively. The median ranges of urinary iodine were 178.2 - 183.9 μg/L in school children, 124.3 - 130.9 μg/L in pregnant women and 72.7 - 109.5 μg/L in lactating women. In Aksu, the medians of iodine concentration in edible iodized salt were 27.1 and 26.5 mg/kg in retail stores and households, respectively. The household coverage rate of iodized salt and the proportion of households using adequately iodized salt were 100.0% (363/363) and 98.9%(359/363), respectively. The median ranges of urinary iodine were 174.8 - 293.0, 154.9 - 230.0 and 135.8 - 239.3 μg/L among school children, pregnant women and lactating women, respectively. The median of iodine concentration in a special edible iodized salt sample reached 49.1 mg/kg, and qualified rate was 0(0/11) in Aksu. Conclusions All provinces , municipalities and autonomous regions ( including the Corps of Xingjiang ) in China have adjusted the iodine content in edible iodized salt in accordance with GB 26878-2011. However, in Tianjin the household iodine concentration in edible salt is lower than the local standards; the household coverage rate of iodized salt and the proportion of households using adequately iodized salt are lower than the national standards; pregnant women and lactating women are at risk of mild iodine deficiency.
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Objective To set up the reference range for thyroid hormones and thyrotropin (TSH) of 8-10 years old school children in certain regions of China to provide reference criteria for diagnosis,treatment,and monitoring of thyroid diseases and related research.Methods A cross-sectional survey was conducted in primary school children aged 8-10 years from six iodine sufficient areas.664 normal school children were selected for establishing reference ranges of thyroid hormones and TSH after crucial screening through questionnaire and laboratory investigation.The serum hormone levels were determined by using chemiluminescent immunoassay (Bayer's reagents),and the reference range of each hormone was displayed as its 95％ central interval.Results The reference ranges of TSH,FT4,FT3,TT4,and TT3 were 1.03-8.42 mIU/L,13.44-20.59 pmol/L,4.75-6.96pmol/L,75.29-152.66 nmol/L,and 1.76-3.35 nmol/L,respectively.There was no significant difference in hormone levels between boys and girls.The eight years old group had slightly higher TT4 level compared with the other age groups.The rural children had higher TSH and TT3 levels and lower FT4 level than the urban children.Conclusion The thyroid hormone and TSH levels are substantially different between school children and adults.Therefore,it is necessary to establish the reference range of thyroid function indices for normal school children in order to diagnose,treat,and monitor thyroid diseases.
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Objective To analyze the median urinary iodine(MUI)level in normal pregnant women based on World HeMth Organization(WHO) recommended criterion,and to provide the MUI reference values for monitoring and evaluating iodine nutrition during pregnancy and related studies.Methods Total 604 normal pregnant and 192 non-pregnant women(as a comparison)were selected from a cross-sectional survey.These women were all healthy,iodine sufficient,with normal thyroid function,and negative anti-thyroid antibodies.The iodine content in drinking water,edible salt,and urine was determined by standard methods,and serum TSH,FT4,FT3,thyroid peroxidaseantibody(TPOAb),and thyroglobulin antibody(TgAb)were measured using chemiluminescent immunoassay.Resuits (1)The iodine in drinking water was 3.0μg/L indicating such small amount of iodine could be neglected for daily iodine intake.(2)All women consumed iodized salt with the median iodine in salt of 31.7 mg/kg.The daily iodine intake of at least 240 μg could be roughly estimated if an average of 10 g salt was taken per person per day and further subtracted by 20%iodine lost during cooking,which could meet the iodine needs during pregnancy.(3)The MUI of 173.1μg/L was calculated from 604 pregnant women having 174.5,167.0,and 180.7 μg/L during the first,second,and third trimesters,respectively,reaching the optimal level of 150-249 μg/L recommended by WHO for pregnant women.However,our data showed relatively lower levels,not reaching 200μg/L.The MUI of 240.2μg/L was calculated from 192 non-pregnant women,reaching the level of"above requirement"(200-299μg/L) recommended by WHO for adults.(4)All women were euthyroid and antibody-negative,but the TSH level in pregnant women was lower than that in non-pregnant women,in particular during the first trimester,while FT4 and FT3 were considerably decreased compared with the non-pregnant(with an exception of FT4 in the first trimester),and both gradually declined with the gestational age.Conclusions The optimal MUI level of 150-249 μg/,L recommended by WHO can be applied to pregnant Chinese women,but our data provided a relatively low range of 150-200μ/L throughout pregnancy.The higher MUI of 240.2μg/L in non-pregnant women indicated that iodized salt with different contents should be supplied on market to meet the requirement of different groups of population.
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Objective:To observe the effect of different iodine intake on the thyroid function in euthyroid adult persons.Methods:One hundred and sixty-one euthyroid healthy volunteers aged 18-24 years were randomly divided into 7 groups.Each group was assigned to receive 500 μg,750 μg,1 000 μg,1 250 μg,1 500 μg,and 2 000 μg iodide/day for four weeks.Serum concentrations of free triiodothyronine(FT3),free thyroxin(FT4)and sensitive thyroid-stimulating hormone(sTSH)were measured by chemolumineseenee assays.Results:Serum FT3 concentration was found a small decline within the normal range in all the iodide supplemented groups(P ＜ 0.05).The level of FT4 was significantly lower,when the dose was up to 1 500 μg (P ＜ 0.05).The level of serum sTSH was increased after 2 weeks iodide supplement in all groups,and after 4 weeks in 500 μg and 750 μg groups(P ＜ 0.05).No significant changes were observed in FT3,FT4 and sTSH between groups(P＞ 0.05).Conclusion:The thyroid function of normal people showed a rise in serum sTSH at a short time and a high-dose of iodine intake.
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Objective:To investigate the effects of exogenous hydrogen peroxide(H_2O_2)on mitochondrial superoxide production and mitochondrial membrane potential changes(△ψ)in fisher rat thyroid cell line(FRTL).Methods:Following 1 mmol/L H_2O_2 exposure in FRTL cells for 10 min,30 min and 24 h,mitochondrial superoxide production was measured by living cell imaging and flow cytometry using MitoSOX.The mitochondrial membrane potential was assayed by spectrofluorimeter and fluorescent microscopy using rhodamine 123(rh123).The cell viability was detected by MTT colorimetric method.Morphological changes were observed by invert microscope.Apoptosis assay was performed by acridine orange staining.Results:Quantitative measurements of the mean intensities of MitoSOX demonstrated significant increase with 1 mmol/L H_2O_2 following 10 min,30 min and 24 h treatment in FRTL cells compared with that of control.Fluorescence intensity of rh123 and optical density of MTr were significantly decreased in FRTL ceils with 1 mmol/L H_2O_2 following 30 min and 24 h treatment(P ＜ 0.01).Under light microscope and fluorescence microscope the characteristic morphological features of programmed cell death,pickuosis,karyorrhexis,and cell shrinkage were observed after acridine orange staining.Conclusion:Acute and chronic exogenous H_2O_2 exposure cause oxide stress in FRTL cells,which result in the increase of mitochondrial superoxide production,△ψdecline,cell necrosis and apoptosis.
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Objective To study mother and infant's iodine metabolism and thyroid function during lactation with different iodine intakes. Methods Wistar rats were randomly assigned to four groups with severe iodine deficiency (SID), mild iodine deficiency (MiID), normal iodine (NI), and excessive iodine (ExI) intake respectively. All rats were fed on an iodine deficient food and drinking water with different quantities of potassium iodide for 3 months until mating. The urinary iodine, milk iodine, blood iodine, and thyroid hormones (TH) were detected in lactating mother and the offspring rats 14 days after birth. Thyroid weight of mother rats was determined. Thyroid morphology of mother and their offsprings was observed. Results ( 1) Iodine contents in urine, milk, and blood of lactating rats and the offsprings were increased with the increase of iodine supplied in diet. But the change in amplitude between groups was decreased in the other; urine iodine > milk iodine > blood iodine. (2) Serum TT4[ (16. 7±12. 0 vs 36.4±15. 0) nmol/L, P<0.05] was significantly decreased, but TSH [(5.73±2.90vs 1. 38±0.30)mIU/L, P<0.01]and TT3/TT4(6.6±2.7 vs 2. l±0.3,P<0.01) were increased in lactating rats of SID group compared with NI, so as TT4( 10.6±2. 3 vs 16.4±4. 7) nmol/L, P<0.05 ] of offspring rats in SID, but were not in MiID and ExI groups. (3 ) Histological studies showed that small follicular thyroid nodules with follicular hyperplasia occurred in both lactating rats and their offsprings in the SID group, mild swelling in MiID group and polymorphism changes appeared in mother rats of ExI group, but no significant difference appeared in offsprings compared with NI group. Conclusions Severe iodine deficiency will lead to hypothyroidism in mother and infant, but normal iodine nutrition and thyroid function in mother and offspring were maintained through the compensatory action of mother and child in mild iodine deficiency and iodine excess.
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Objective To investigate the sodium iodide symporter (NIS) gene expression during different iodine intakes and its function in thyroid autoregulation. Methods BabL/c mice were randomly divided into five groups according to their different iodine intake levels : low iodine (LI), normal iodine (NI), five-fold iodine (5HI) ,ten-fold iodine (10 HI) and fifty-fold iodine (50 HI). After three months and six months administration, they were sacrificed and thyroids were excised. The mRNA and protein expression level were determined by real time quantitative PCR and immunohistochemistry respectively. Iodine content in thyroid tissue was measured with spectrophotometry and thyroid hormone level was measured with radioimmunoassay. Results Compared with NI group, NIS mRNA and protein expression was greatly increased in LI groups. Immunohistochemistry analysis indicated that NIS was mostly located at the basolateral membrane of thyrocyte,suggesting the improved activity in transporting iodine. But when faced with long-term and severe iodine deficiency, the iodine content in thyroid was finally decreased ,and hormone level lowered. On the other hand, in HI groups NIS mRNA and protein expression was greatly down-regulated. There was a tendency of decreasing NIS gene expression level with increasing doses of iodine intakes. In addition, NIS protein was found mainly in intracellular vesicles, rather than at the cell membrane,suggesting the loss of its activity. The iodine content in thyroid tissue was only slightly increased and was not consistent with the iodine intake levels. Conclusion These findings indicate that NIS may be. regulated at transcription, translation and post-translation levels. This phenomenon constitutes a highly specialized intrinsic autoregulatory system that protects thyroid from high doses of iodine, but at the same time ensures adequate iodine uptake for hormone biosynthesis. NIS plays a critical role in thyroid autoregulation mechanism.
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Objective To set up the trimester-specific reference ranges of thyroid hormones for normal pregnant women to provide reference criteria for diagnosis, treatment and monitoring or screening of thyroid disease during pregnancy and related research. Methods A cross-sectional survey was conducted in pregnant and non-pregnant women in iodine sufficient areas. A total of 505 normal pregnant women and 153 normal non-pregnant women (as control) were selected for establishing trimester-specific reference ranges of thyroid hormones after rigorous screening through the survey questionnaire and laboratory tests. Thyroid hormones were measured by Bayer automated chemiluminescence immunoassay, and the reference range of each hormone was calculated as median (the 50th percentile value) and two-sided limits (the 2.5th and 97.5th percentile values). Results All women investigated were in iodine sufficient status within optimal urine iodine level. The serum TSH level during the 1st trimester was obviously declined compared with that in the non-pregnant individuals (P < 0.01), and started to rise during the 2nd trimester, but was still not restored to non-pregnant level until the 3rd trimester. Serum FT4 and FT3 levels gradually decreased from the 2nd trimester to the 3rd (P < 0.01), and the TT4 and TT3 levels were markedly elevated since early pregnancy (P < 0.01) and reached peak levels at the 2nd trimester approximately making up to 1.5 times of those in the non-pregnant individuals. Conclusion The thyroid hormone levels during pregnancy differ completely from those of the non-pregnant individuals, and also differ during different gestation periods. Therefore, to establish trimester-specific reference data of thyroid hormones during normal pregnancy may be important for clinical practice.
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BACKGROUND: Triiodothyronine (T3) is an important regulation factor at the critical period of brain development. It maybe control the successive differentiation during the development of central nervous system (CNS).OBJECTIVE: To monitor the differentiation of neural stem cells (NSCs) induced by T3 and the thyroid hormone receptor (TR) mRNA expression changes.DESIGN: Open experiment.SETTING: Department of Pathology, Tianjin Medical College of Chinese People's Armed Police Force; Institute of Endocrinology of Tianjin Medical University.MATERIALS: This study was carried out in the Tianjin Medical University between January 2003 and March 2005.Ten-to-twelve-week-old aborted fetuses were obtained from the General Hospital of Tianjin Medical University with the approval of the local ethical committee. Informed consents were obtained from the mothers and their relatives.METHODS: ①Under the aseptic condition, the bilateral cortex of human fetal brain was removed and dissociated by brief mechanical trituration in D-Hanks. Then, 20 μg/L bFGF and 30 nmol/L T3 were used to induce the proliferation of NSCs and inoculated to poly-L-lysine-coated 24-well plate and 25 mL culture flask for routine culture at 1 ×109 L-1. The culture medium was DMEM/F12 serum-free complemented with N2. Half of the culture medium was changed every 48 hours.Seven days later, bFGF was discarded, only T3 was used for induction and differentiation. ② At 1, 2 and 3 weeks of culture, cells were collected, and RT-PCR was semiquantitatively used to detect TR mRNA expression changes at different stages of differentiation of NSCs. Isoforms were identified by immuocytochemistry.MAIN OUTCOME MEASURES: ①Cellular morphology observation and isoforms identification before and after differentiation of NSCs induced by T3. ② TR mRNA expression changes during the differentiation of NSCs.RESULTS: ①The hNSCs were round and had a smooth surface and gradually gathered to neurospheres. The proliferative hNSCs were nestin-positive and incorporated BrdU. When NSCs were induced by T3 for one week, most of the cells took on monopole or double poles, and had long and thin processes. The differentiated cells were neurofilament protein (NFP)-positive, galactocerebroside (GC)-positive or glial fibrillary acidic protein (GFAP)-positive. When NSCs were induced by T3 for three weeks, most of the cells were big, with unclear cell membrane, round nucleus, many thick processes which had many branches. The spider-like cells were scattered, and 80% of the cells were myelin basic protein-positive. ② TRα1 mRNA expression level was the highest before inducing NSCs. With the induction of T3, the expression level was decreased gradually, and was the lowest at 2 weeks, and then was rebounded gradually, but the final level was still lower than that of NSC (F =32.49, P =0.008). The tendency of TRα2 mRNA expression alteration was identical with that of TRα1 mRNA. TRβ1 mRNA expression level was the lowest in NSC, was increased gradually with the induction of T3 and attained the highest level at 2 weeks of induction of T3. Furthermore, the expression level of TRβ1 mRNA was also higher than that of TRα1 at the same time (t =15.64,P =0.001), and it reached the lowest level at 3 weeks of the induction. TRα3 expression level was firstly decreased after the differentiation induced by T3, and was close to the expression level of NSC at 2 weeks of induction (F =51.94, P =0.378), then was decreased to lower lever.CONCLUSION: T3 can induce NSC to differentiate into neurons, oligodendrocyte and astrocytes. TR mRNAs are expressed in different time intervals during the differentiation of NSCs.
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Thyroid function ultimately depends on appropriate iodine supply to the gland. Thyroid hormone deiodination is an intrinsic component of the thyroid hormone homeostasis. Type Ⅰ iodothyronine deiodinase (D1) plays an important role in thyroid hormone metabolism and has close relationship with thyroid function. Based on successfully establishing animal models of iodine deficiency and iodine excess in Babl/c mice (Babl/c mice were randomly divided into five groups: low iodine (LI), normal iodine (NI), five-fold iodine (5HI) , ten-fold iodine (10HI) and fifty-fold iodine (50HI) group. Three months and six months after admistration, they were sacrificed and thyroids were excised), the expression level of D1 mRNA were examined by using real time quantitative PCR method. D1 activity was analyzed by 125I-rT3 as substrate combined with ion-exchange chromatography. The thyroid hormone was measured with radioimmunoassay method. The data revealed that in the case of iodine deficiency, both D1 mRNA expression and D1 activity was greatly increased(compared with NI groups, P
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Objective:To study the master iodine nutrition status of population living in areas with different iodine in drinking water and the cut-off point of stopping iodized salt supply and the range of adequate iodine intake for the strategy of prevention from iodine deficiency or excess. Method:Thirteen townships points along the Yellow River downstream in Shandong were investigated and divided into six groups(A-F) based on water iodine concentrations of 0-50,50-100,100-150,150-300,300-800 and over 800 ?g/L. The indicators of water iodine,edible salt iodine,urinary iodine(UI) and thyroid goiter were observed. Results:From A,B,C,D,E and F group,the medians of water iodine concentration were 20.3,91.4,143.2,203.6,341.9 and 812.3 ?g/L,of edible salt iodine were 0,25.7,25.8,30.4,36.4 and 33.0 mg/kg,and of UI were 116.8,354.2,400.4,607.9,881.3 and 1 213.8 ?g/L respectively. The goiter rates were 10.8,8.6,15.0,14.2,14.9 and 25.0 % respectively . The sample proportion of UI below 100 ?g/L was 8.2%,of 100-300 ?g/L was 18.2% and of over 300 ?g/L was 73.6%. Frequency excursion of UI had a high trend towards water iodine concentration over 90?g/L in 5 groups. The proportion of UI over 300 ?g/L increased,consistent with higher water iodine level. Median UI of all groups with iodized salt decreased significantly,especially group F. There were significant correlations between UI and water iodine. Iodine nutrition status was markedly excessive in group B,C,D,E and F. Conclusions:Iodine nutrition status of most residents consuming drinking water with iodine concentration about 20 ?g/L should be adequately supplied with eligible iodized salt. Iodine intakes in groups B-F were excessive,and iodized salt supply should be stopped there. The cut-point of water iodine level where iodized salt stopped could possibly be 90 ?g/L,and the range of adequate iodine intake,in terms of drinking water,could be defined at range of over 20 to 90 ?g/L in iodine concentration.
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Objective: To further investigate the effects of iodine intake on thyroid function and its possible mechanism. Method: Wistar rats were randomly divided into six groups: LI, NI, 5HI, 10HI, 50HI, 100HI. Different groups of rats were fed with feed and water of different iodine content. 3, 6 and 12 months after administration, they were sacrificed and thyroids were excised. The thyroid D1 mRNA expression level was determined by RT-PCR semi-quantitative method and the thyroid D1 activity was analyzed by using 125I-rT3 as substrate. Results: Compared with NI group, the thyroid D1 mRNA expression was decreased in all HI groups, and D1 activity was significantly higher in LI group and lower in HI groups. There was a tendency of decrease in D1 activity with increased doses of iodine intakes. Conclusion: In the case of iodine deficiency, thyroid D1 activity will increase greatly in order to convert more T4 to T3, but deficient iodine intake doesn’t improve thyroid D1 mRNA expression. Excess iodine can inhibit both thyroid D1 mRNA expression and its activity.
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Objective To observe the variations of thyroid hormone receptors(RTs) mRNA experession during the human brain devlopment. Methods We investigated the ontogeny of TR isoforms in the first and second trimester human fetal different brain areas by semi-quantitative reverse transcriptase-polymerase chain reaction analysis. When we amplified the TR? 2 by PCR, the other sequence was amplified at the same time, it is about 100pb less than the RT? 2, so we cloned it into pGEM-T easy vector to determine its sequence. Results In the first and second trimester human fatal brain, RTs mRNAs were detected in cerebrum, cerebellum, brain, stem, hippocampus, spinal cord, thalamus. TRs mRNAs were relatively higher in cerebrum, cerebellum, hippocampus. In the first trimester human fatal brain, the TR? isoforms mRNAs were higher than TR? 1, In the second trimester human fatal brain, the TR? 2 and TR? 1 were higher than TR? 1. An additional truncated species was detected with the TR? 2 primer set. We submitted its sequencing results to Genbank, comparing it with TR? 2 by BLAST software, the results showed that it is identical to TR? 2 with the exception that it is missing 42 amino acids at 371-412 of TR? 2 sequence, so it is the human TR? 3. At the same time we acquired the Genbank accession number AF522368. Conclusion The spatial and temporal expressions of TR isoforms mRNAs exist in CNS development. We firstly assure the different sequence between human TR?2 and TR?3.
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<p><b>OBJECTIVE</b>To estimate the role and extent of iodine deficiency, iodine supplement and iodine excess on mental development of children.</p><p><b>METHODS</b>Meta-analysis was applied to study 128 independent items from 63 published and non-published papers and reports. The standards of references collected included: age of sample declared by references was 5 - 15; belong to comparison study; children lived in iodine deficiency disorders (IDD) and iodine excess areas; no difference of social economic and culture development level between the study group and the control group.</p><p><b>RESULTS</b>Sixty-seven percent and 79% of the reports mainly involved severe IDD areas respectively. Hunter test of each studies, i.e. iodine deficiency, iodine supplement and excessive iodine group had not discovered statistic difference at the level of alpha = 0.05. The weighted average ES of damage affecting on children's intelligence by iodine deficiency achieved 0.69, which was equivalent to a marked drop in 10.4 IQ points [95% confidence interval (CI): 9.9 - 10.9] when comparing with the children living under non-IDD. The weighted average ES of protective effect on children's intelligence by iodine supplement reached 0.81, which meant that the IQ of children born after correction of iodine deficiency increased 12.2 points (95% CI: 11.5 - 12.9) in comparison with those born at least one year before the correction of iodine deficiency. Most of the references about the relationship between iodine excess and intelligence were gathered from proceedings, while the others were from journals. They location were in some areas of Shandong, Hebei, Shanxi and Inner Mongolia. The mean ES of the role of iodine excess on intelligence was 0.21, which was corresponding to 3.2 IQ points (95% CI: 2.5 - 4.0).</p><p><b>CONCLUSION</b>1) Iodine deficiency played a role of intermediate strength compared with other causes in delaying brain development making children to be at least 10 IQ points loss in IDD areas. 2) Effective iodine supplement plays a remarkable strengthening role in promoting brain development and can cause 12 IQ points increase for children who were born after the correction of iodine status. 3) Iodine excess has not shown significant important role in children's intelligence.</p>
Subject(s)
Child , Child, Preschool , Humans , China , Intelligence , Iodine , Pharmacology , PoisoningABSTRACT
FRTL cells were incubated in the culture medium containing 10 -6 -10-3 mol/L KI for 24, 48 and 72 h, and the levels of sodium iodide symporter (NIS) mRNA and protein were measured using RT-PCR and Western blot. The levels of NIS mRNA in FRTL cells incubated with different concentrations of iodide for 24 and 48 h showed no significant difference as compared with the control group, however, NIS protein was reduced gradually in FRTL cells incubated with different concentrations of iodide for 48 and 72 h as compared with that in control group. The higher the iodide concentration, the lower the levels of NIS protein. The results show that acute iodine excess does not affect the expression of NIS mRNA, but down-regulates NIS protein expression. Iodine excess may regulate the expression of NIS through post-transcription.
ABSTRACT
The choline acetyltransferase (CHAT) and the molecular forms of acetyl-cholinesterase (ACHE) activites in various brain regions of 20-day-old hypothyroid and hyper-thyroid rats were measured. The results provided the following information: 1) CHAT and ACHE activities were directly interrelated with thyroid hormones. 2) In both hypothyroid and hyperthyroid rats the nonextractable ACHE activity was distinctly decreased in every brain region, suggesting that both conditions were affected in the critical period of cholinergic synaptic development. 3) The ratio of membrane-bound ACHE to soluble ACHE decreased;it showed that thyroid hormone deficiency might distrub development and maturation of cholinergic neurons. 4) In most regions of the central nervous system,the CHAT seemed to be more affected than ACHE by thyroid hormones.