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ObjectiveTo observe the thyroid status of pregnant women during the 1st and 2nd trimester of gestation,and its role in brain and neural development of their offspring's.MethodsFrom 2008 to 2009,pregnant women from nine townships of two counties in Wushi and Baicheng in Aksu prefecture of Xinjiang were selected as research subjects according to the survey standard.After informed consent signed,their urinary iodine,serum thyroid stimulating hormone(TSH) and free thyroxin(FT4) were analyzed.The value of thyroid hormone of normal pregnant women was used in diagnosis of subclinical hypothyroidism and hypothyroxinemia in pregnant women.From 2010 to 2011, The brain and neural development status among offspring born by those pregnant women were evaluated with DDST.In accordance with the results of Denver Development Screen Test (DDST) screening,pregnant women were classified into survey and control groups,and the survey group was the suspicious and abnormal of the result of DDST screening(delay),the control group was normal of the result.According to gestational age,pregnant women were divided into 4 gestation groups:G1(6 to 13 weeks),G2(14 to 18 weeks),G3 ( 19 to 23 weeks) and G4(24 to 28 weeks).ResultsA total of 396 cases of pregnant women during the 1st and 2nd trimester of gestation were investigated(survey group 102 cases,control group 294 cases).The median value of urinary iodine concentration among pregnant women in survey group was 152.4 μg/L The prevalence of subclinical hypothyroidism and hypothyroxinemia among pregnant women was 10.78％(11/102) and 3.93％(4/102),respectively.In control group,the median value of urinary iodine concentration was 180.0 μg/L The prevalence of subclinical hypothyroidism and hypothyroxinemia among pregnant women was 7.48％ (22/294) and 4.42％ (13/294),respectively.During the pregnant period from G1 to G3,the median serum TSH of pregnant women in DDST survey group (2.24,3.49,2.85 mU/L) was higher than that of DDST control group( 1.59,2.70,2.28 mU/L).Especially,the difference of TSH between the two groups during the period of G3 was statistically significant (t =4.906,P ＜ 0.05 ).ConclusionsHypothyroidism tendency of pregnant women during the period from gestation week 19th to 23rd may be an important factor in the development of brain abnormalities of their offsprings.
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Objective To explore the effect of short-term iron deficiency on thyroid function of rat and its mechanism, and to provide new clues and ideas for prevention and control of iodine deficiency disorders. Methods Twenty-two healthy SPF/VAF level weaning male SD rats were randomly divided into control group(iron content in diet was 65 mg/kg) and iron deficiency group(iron content in diet was 15 mg/kg) by body weight, and 11 in each group respectively. After 4 weeks feeding, body weight and thyroid glands weight were measured, and the relative weight of thyroid gland was calculated. Rat whole blood was collected and serum was separated. Hemoglobin, serum iron levels and total iron binding capacity were tested using biochemical assay;serum free iodine thyroid three original acid (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) levels were detected by chemiluminescence;after thyroid were fixed in formalin, embedded with paraffin and sectioned regularly, and immunohistochemical stained, the protein expression of thyroid peroxidase(TPO) was observed. Results Compared with control group [(243.8 ± 16.4)g], iron deficiency group of animals had less body weight[(214.3 ± 18.1 )g, t = 4.002, P ＜ 0.01];there was a lower absolute thyroid weight in iron deficiency group[(11.9 ± 1.6)mg]than in control group[(13.4 ±1.3)mg, t = 2.369, P ＜ 0.01], but no significant changes of the relative weight of thyroid gland between the two groups[(0.055 ± 0.004),(0.055 ± 0.006)g/kg, t = 0.162, P ＞ 0.05]. Hemoglobin and serum iron in iron deficiency group were ( 100.4 ± 8.9)g/L and (7.0 ± 0.8)μmol/L, which were less than that in control group[( 146.5 ±16.3)g/L, (26.1 ± 5.1 )μmol/L, t = 8.233,12.277, all P ＜ 0.01]. Total iron binding capacity in control group was (74.0 ± 4.6)μ mol/L and that in iron deficiency group[(124.8 ± 6.3)μmol/L], and the difference was significant (t = 21.531, P＜ 0.01). At the same time, their serum hormones FT3, FT4 and FT3/FT4[(4.71 ± 0.53), (29.69 ±2.63)pmol/L, 0.16 ± 0.02]were lower than that in control group[(5.69 ± 0.61),(31.98 ± 2.49)pmol/L, 0.18 ±0.01, t = 4.044,2.096,3.255, P ＜ 0.01 or ＜ 0.05]. The expression of TPO protein decreased in iron deficiency group than in control group. Conclusions Iron deficiency reduces thyroid function, which perhaps is due to the reduction of TPO activity. Combined supplementation of iodine and iron will possibly improve the prevention effect on iodine deficiency disorder in iron deficiency areas.
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ObjectiveTo establish a new method with low usage amount of arsenic trioxide for measuring 300 - 1200 μg/L high concentration iodine in urine by As3+-Ce4+ catalytic spectrophotometry using ammonium persulfate digestion, which would be convenient for monitoring urinary iodine in excessive iodine regions and to reduce environmental arsenic pollution. Methods Calibrators and urine samples(0.20 ml each) were digested according to the current standard detection method of urinary iodine(WS/T 107-2006). At the same time, improving the current standard method, the amount of arsenious acid solution was reduced from 0.100 moL/L H3AsO3 (containing NaCl 25 g/L) 2.5 ml to 0.025 mol/L H3AsO3(containing NaCl 40 g/L) 2.5 ml; amount of ceric ammonium sulfate solution was reduced from 0.076 mol/L 0.30 ml to 0.025 mol/L 0.50 ml; and photometric wavelength was changed from 420 nm to 380 nm. The new method was evaluated by standard curve linearity and linear range, sample detection precision, accuracy, and the results of urinary iodine were compared with those determined bycurrent standard method, and this new method was also tested of suitable combination of reaction temperature and reaction time of cerium arsenic in the temperature range of 20 - 30 ℃. Results The calibration relation of C =a + blgA (C: iodine concentration, A : measuring absorhance) in the new method existed when As3+- Ce4+ catalytic reaction was kept at a certain stable temperature range between 20 - 30 ℃ and in certain fixed reacting time. The linear range of the calibration curve was 300 - 1200 μg/L and the linear correlative coefficient was- 0.9999. The relative standard deviations(RSD) were 1.0％(3.2/330.3), 0.4％(2.0/517.3), 0.5％(3.9/712.6) and 0.9％(9.4/1042.3) when measuring urine samples with iodine concentration of 330.3, 517.3,712.6, and 1042.3 μg/L, respectively. The total average recovery was 98.3％ with a range of 93.4％ (186.8/200.0) - 101.5％ (202.9/200.0) when measuring 4 urine samples containing different concentration of high iodine, and average recovery was 99.1％ (148.6/150.0), 97.5％ (195.0/200.0), 98.8％ (395.3/400.0), and 98.2％ (392.7/400.0),respectively. The test results of four urinary iodine standard materials were all within the given value range and the relative deviations(RD) were all ＜ 2.0％ at different test temperature, respectively. No significant difference was found between the results of the 16 urine samples containing high concentration of iodine determined by the new method and the current standard method (|t| =0.727, P ＞ 0.05). The table of suitable combination of As3+-Ce4+ reaction temperature and reaction time for this method was obtained(such as 20 ℃ and 33 min, 25 ℃ and 25 min,30 ℃ and 19 min, etc). Conclusions This method greatly reduces the amount of arsenic in waste, reduces pollution, saves reagents, and this method is easier to be performed with better precision and accuracy, which is suitable for measuring high concentration of iodine in urine.
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Objective Take alkaline ashing method as golden standard to explore the accuracy of chloric acid digestion method in determination of human milk iodine. Methods Sixty one breast milk samples collected in Hexi district of Tianjin was measured by the method for determination of iodine in foodstuff by As3+-Ce4+ catalytic spectrophotometry (referred to as the alkaline ashing method) published in 2008 and the method for determination of iodine in urine by As3+-Ce4+ catalytic spectrophotometry(referred to as acid digestion) published in 1999, respectively. were highly correlated(r = 0.960, t = 26.3, P < 0.01), and the regression equation was (Y) = - 28.1 + 0.808X, in which X was independent variable, that is the results of alkaline ashing method; (Y) was dependent variable, that is the estimated data of chloric acid digestion method. The average difference of the results measured by the two methods was 68.3 μg/L, and the results from chloric acid digestion was 38.9% which lower than that of alkaline samples were diluted by 3,4 and 5-fold and then digested by chloric acid, the liquid clarification rates were 80.3% ashing and chloric acid digestion method were, respectively, 165.4, 110.0 μg/L. Conclusions Compared with alkaline ashing method, the results determined by chloric acid digestion method are significantly lower. It is suggested that there are systemic errors in chloric acid digestion method, which means that alkaline ashing method can not be replaced by the chloric acid digestion method.
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Objective To study the expression level of thyroid insulin-like growth factor-Ⅰ (IGF-Ⅰ) in iodine deficiency and excess mice and the effect of thyroid gland IGF-Ⅰ in the thyroid morphological change. Methods Forty-eight Balb/c mice were chosen as studied objects,weighing about 16 g. They were divided into three groups: low iodine(LI,iodine content of 50 μg/kg in feed,drinking deironized water) group,normoi(NI,iodine content of 300 μg/kg in feed,drinking deironized water) group and high(HI,iodine content of 300 μg/kg in feed,iodoine of content 14 700 μg/kg in drinking) group,16 mice in each group. Mice were put to death after 12 weeks and taken out of their thyroid gland. The body weight,absolute and relative weights of thyroid gland were measured and the morphological change of thyroid gland were observed under microscope. The expression levels of thyroid gland IGF-Ⅰ mRNA and protein were detected by RT-PCR and immunohistochemistry,respectively. Results There were statistical significances between groups of thyroid absolute and relative weights(F = 315.881,405.921,all P < 0.01). LI group [(10.71±4.03) mg,(44.98±15.39)mg/100 g body weight]and HI group [(3.42±1.17)mg,(13.50± 3.89)mg/100 g body weight]had heavier thyroid absolute and relative weights than NI group[(2.11±0.53)mg,(8.35±1.98)mg/100 g body weight,all P < 0.01]. Under microscopy,the thyroid follicle capacity grew down and the follicle quantity grew up in LI group,the epithelium was stylolitic,the colloid diminished or absence in follicular cavity,while HI group presented colloid accumulation without follicular hyperplasia. The expression level of thyroid gland IGF-Ⅰ mRNA in LI group(1.03±0.32) was more than that in NI(0.65±0.19) and HI(0.59± 0.20) groups(F= 7.518,P< 0.01). In contrast to NI,there was no difference in the expression level of thyroid gland IGF-Ⅰ mRNA in HI group(P > 0.05). The brownish particles of LI group were more than NI and HI groups in the thyroid follicle epithelium by immunohistochemistry,while HI group was less than NI group. Conclusions The mice of iodine deficiency presented follicular hyperplasia goiter,the mice of iodine excess presented colloid accumulative goiter. The change of IGF-Ⅰ mRNA and protein expression may participate morphologleal change,indicating autocrine IGF-Ⅰ of thyroid gland may play an important role in regulating goiter formation.
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Objective To investigate the iodine nutritional status of school children, lactating women and infants in iodine deficient areas of Baicheng and Wushi Counties in Xinjiang Autonomous Region. Methods According to the geographic location of east, south, west and north of county, 10 primary schools of 8 townships were selected. In each school, 10 children among each gender and age group from 8 to 10 years old were selected. A total of 300 school children were chosen. One hundred and four infants aged 0-2 years old and their mother were selected in 8 townships. Iodine content in edible salt at household level, the urinary iodine in school children and lactating women, total goiter rate(TGR) and the status of the intelligence quotient (1Q) of school children, the status of psychological development of infants were observed. Direct titration assay for testing the salt iodine, colorimetric ceric-arsenic assay and vitriolic ammonium assimilation were used for testing urinary iodine. The size of thyroid gland was measured by palpation. The Combined Raven Test for Chinese Rural was used to test the IQ. The psychological development of infants was tested by Danver Development Screening Test (DDST). Results The coverage rate of iodized salt at household level was 73.1% (123/182), however, the proportion of households using adequately iodized salt was 64.1% (118/182). The medium of urinary iodine in school children was 103.7 μ/L, with 47.8%(75/157) less than 100 μg/L and 28.0% (44/157) less than 50 μg/L; it was 123.0 μg/L in Baieheng County, with 44.4%(28/63) less than 100 μg/L and 33.3%(21/63) less than 50 μg/L; it was 100.3 μg/L in Wushi County, 50.0%(47/94) less than 100 μg/L and 24.5%(23/94) less than 50 μg/L. The medium of urinary iodine in locating women was 143.3 μg/L, it was 119.7 μg/L and 184.6 μg/L in Baicheng and Wushi Counties, respectively. The total rate of goiter in school children was 14.3%(43/300), it was 10.8%(13/120) and 16.6%(30/180) in Baicheng and Wushi Counties, respectively. The average IQ in school children was 80.6±11.6, it was 83.0±11.6 and 79.0±11.7 in Baicheng and Wushi Counties, respectively. The proportion of mental retardation in school children (IQ≤69) was 13.0% (39/300), it was 6.7% (8/120) and 17.2%(31/180) in Baicheng and Wushi Counties, respectively. In addition, the proportion of psychological development in infants being normal, suspicious and abnormal was 78.8%(82/104), 12.5% (13/104) and 8.7%(9/104), respectively. Conclusion This study confirms the fact that there is also existence of mental retardation in children and infants, caused by iodine deficiency.
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Objective To study the effects of iodine deficiency during pregnancy on fetal iodine metabolism and thyroid function. Methods Wistar dams were randomly divided into four groups: severe iodine deficiency(SID), moderate iodine deficiency(MoID), mild iodine deficiency(MiID) and normal iodine(NI). All the dams were fed with iodine deficient food(iodine contents: 50 μg/kg) and drinking water with different doses of KI (0,54.9,163.8,381.7 μg/L) for 3 months till mating. Iodine was supplied at the dose of 1.24 μg/d(SID), 2.50 μg/d(MoID), 5.00 μg/d(MiID) and 10.00 μg/d(NI), respectively. The dams and their fetuses on gestation of 20 days were studied. Urine iodine of dams and iodine contents in fetal amniotic fluid were measured by As3+-Ce4+catalytic spectrophotometry using ammonium persulfate digestion. And blood iodine in pregnant rats and iodine contents in placental tissue were measured by As3+-Ce4+catalytic spectrophotometry in dry ash of samples in KClO3-ZnSO4-K2CO3-NaCl. Thyroid hormone levels in mother serum and in fetal amniotic fluid were detected by chemiluminascent assay, and their thyroid glands were weighted and carefully observed. Results ①Iodine content in urine and blood of pregnant rats and amniotic fluid of fetal rats reduced along with their decrease of iodine supply. Urine iodine median of rats in 4 groups(NI: 353.7 μg/L; MiID: 115.9 μg/L; MoID: 26.9 μg/L; SID: 0 μg/L) were statistically significant(χ2=32.884, P < 0.01). Blood iodine level in MoID and SID[(29.4±18.6), (11.7± 7.0)μg/L]was significantly lower than that in NI[(49.1±23.0)μg/L, P < 0.05 or < 0.01]. In iodine deficiency groups, there was a decreasing trend in iodine contents of fetal amniotic fluid[MiID: (48.3±23.1)μg/L; MoID: (29.2±14.7)μ/L; SID:(19.5±6.7)μg/L]and an increasing tendency in iodine contents of placental tissue [MiID: (0.57±0.26)μg/g, MoID: (0.53±0.34)μg/g; SID: (0.53±0.15)μg/g], but there was no statistical significance(P>0.05). ②In SID, TT4[(14.3±4.1)nmol/L]and FT4[(10.8±3.6)pmol/L]were lower than that in NI[(28.4±19.3)nmol/L, (20.2±8.0)pmol/L, P < 0.05 or < 0.01], while that in MoID[(22.1±6.1)nmol/L, (18.5±4.1)pmol/L]and MiID[(25.5±13.1)nmol/L, (18.6±8.4)pmol/L]were decreased without statistical significance(P > 0.05). And FT3/FT4 ratio(0.34±0.16), absolute[(48.4±22.7)mg]and relative weights[(144± 76)mg/kg]of thyroid gland in pregnant rats were respectively higher than that in NI[0.16±0.02, (19.5±3.1)mg, (66±10)mg/kg, P<0.01]. But that in MoID[0.19±0.04, (27.0±5.7)mg, (84±19)mg/kg]and MiID[0.17± 0.06, (25.0±8.9)mg, (78±25)mg/kg]were increased without statistical significance(P > 0.05). A visibly congestive enlargement thyroid was found in SID, while thyroid mildly enlarged in MoID and MiID. ③Compared with NI [(2.38±1.55)pmol/L,0.50±0.18], the FT4 levels [(1.07±0.87) pmol/L]in amniotic fluid were significantly decreased (P < 0.05) and the FT3/FT4 ratio (1.96±0.61) was significantly increased (P < 0.01) in SID. There were no statistical significances(P > 0.05) in other 3 groups[MiID: (2.77±0.90)pmol/L,0.46±0.15; MoID: (2.35±0.76)pmoL/L,0.61±0.21]. A visible thyroid enlargement with hyperemia was observed in SID fetus while in other 2 experiment groups their thyroids were only mildly congested. Conclusions Severe iodine deficiency during pregnancy can result in both mother and fetus overt hypothyroidism. The fetal thyroid hormone levels in mild iodine deficiency status is close to normal levels because of maternal and placental compensation. Moreover, both the dam and the fetus suffer from the negative effects in moderate iodine deficiency during pregnancy.
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Objective To investigate the effect of seafood intake on the urinary iodine level in women for exploring an alternative to iodine supplementation.Methods Healthy pregnant women and non-pregnant women, aged 20～40 years,were selected during their health examination in local women'S health care in 2006.The types of seafood and its intake frequency were recorded from these women.and urine and kitchen salt samples were collected for iodine determination.Results A total of 198 women including 148 pregnant and 50 non-pregnant women were recmitod for this study;they had a median level of urine iodine of 87.51 mg/L.The median levels of urine iodine of83.49,91.52,166.45μg/L in three group women classified as hardly,seldom and often intake of see food showed significant difference(X2=6.202,P<0.05).Urine iodine level in non-pregnant women taking seafood (90.94μg/L)was higher than that in pregnant women(84.79μg/L),the difference being statistically significant (U=3318.00,P<0.05).The urine iodine in pregnant women with seldom intake of seafood(94.46 μg/L)was significantly higher than that in the hardly intake women(83.28 μg/L),the difference being statistically significant (U=1257.5,P<0.05).During late period of gestation,the urinary iodine in the women ofthree statUS of hardly. Seldom and often intake of seafood were 81.93,97.97 and 140.18 μg/L,respective,with significant differences among them.Conclusions A certain amount of seafood taken every week Can increase urine iodine levels,and a direct relationship Was observed.Therefore,we suggest that it is necessary to advocate taking seafood to pregnant women for prevention of cretinism,particularly in the air.as where iodized salt was difficult to implement.
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<p><b>BACKGROUND</b>Type 1 deiodinase (D1) plays an important role in the metabolism of thyroid hormone and has close relationship with thyroid function. In this study we explore the effects of iodine intake on D1 activity and its mRNA expression and its possible mechanism.</p><p><b>METHODS</b>Forty-eight Wistar rats were randomly divided into six groups with 8 in each: low iodine (LI), normal iodine (NI), five-fold iodine (HI(5)), ten-fold iodine (HI(10)), fifty-fold iodine (HI(50)), one hundred-fold iodine (HI(100)) group. Three months, six months and twelve months after admistration of potassium iodate, they were sacrificed and thyroids were excised. The expression of D1 mRNA in the thyroid tissue was determined by RT-PCR and D1 activity was analyzed by (125)I-rT3 as substrate. The thyroid hormone was measured with radioimmunoassay method.</p><p><b>RESULTS</b>Compared with NI group, D1 mRNA expression in LI groups slightly decreased, and D1 activity greatly increased. Both T(3) and T(4) in thyroid tissue significantly decreased, but the T(3)/T(4) ratio increased. D1 mRNA expression decreased in all HI groups, and D1 activity was significantly lower in HI groups. There was a tendency of decrease in D1 activity with increased doses of iodine intakes. There was no significant difference in T(4) in thyroid tissue between HI groups and NI group, but a tendency of decrease in T(3) level was found in all HI groups.</p><p><b>CONCLUSIONS</b>In the case of iodine deficiency, D1 activity increased greatly in order to convert more T(4) to T(3). Excess iodine can inhibit both D1 mRNA expression and its activity to protect organism from being injured by excessive T(3).</p>
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Animals , Rats , Iodide Peroxidase , Genetics , Metabolism , Iodine , RNA, Messenger , Rats, Wistar , Thyroid Gland , Thyroxine , Blood , Triiodothyronine , BloodABSTRACT
Wistar rats with different levels of iodine nutrition were killed after 3,6 and 12 months of experiments.Serum thyroid hormones were assayed with RIA.The activity of typeⅠdeiodinase(DⅠ)and typeⅡdeiodinase(DⅡ)was measured based on the release of radioiodide from the ~(125)Ⅰ-labeled substrate.The result showed that hypothyroidism reflected by decreased T_4 happened during the initial phase of iodine deficiency.The activity of DⅠand DⅡin rats was raised significantly in iodine deficiency groups.An excess of iodine inhibited DⅠactivity resulting in decreased serum TT_3 and FT_3.However,DⅡactivity increased in rats with iodine excess, attributing to the inactivation of T_3 and T_4 to the substrate of DⅡenzyme.