Search

To determine the factors that influence the development of abnormal thyrotropin (TSH) level in an euthyroid population.We conducted a follow-up study in 3 communities with different iodine status. Of the 3403 euthyroid subjects at baseline screened in 1999, 80.1% (n = 2727) was visited and sampled in 2004 for measuring TSH, thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb).Iodine status in the 3 communities were stable. Decreased TSH level (0.3 mU/L) developed in 2.5% (n = 68) of sampled subjects, while raised TSH level (4.8 mU/L) in 2.4% (n = 64). A logistic analysis showed that risk factors for developing decreased TSH level included positive conversion of TPOAb (OR = 5.5), positive TPOAb both in 1999 and in 2004 (OR = 4.0), positive TgAb in 2004 (OR = 3.7) and TSH1.0 mU/L in 1999 (OR = 2.6). Risk factors involved in developing raised TSH level included iodine status of Zhangwu community (OR = 4.1), iodine status of Huanghua community (OR = 3.9), positive TgAb in 2004 (OR = 3.7), positive TPOAb both in 1999 and 2004 (OR = 3.6), positive conversion of TPOAb (OR = 2.7) and TSH1.9 mU/L in 1999 (OR = 2.6).Exposure to long-term iodine excess imposes danger of developing hypothyroidism. The risk will be even higher when exposing to iodine adequacy after correction of iodine deficiency. An interval between 1.0 and 1.9 mU/L of TSH level was optimal with the least probability of developing abnormal TSH level.

To investigate the prevalence of gestational transient thyrotoxicosis (GTT) and analyze the cause of thyrotoxicosis encountered in this period.An epidemiologic survey in ten hospitals in Shenyang was performed and 534 pregnant women during the first trimester of pregnancy filled questionnaire, received physical examination and had serum thyroid-stimulating hormone (TSH), free T(4) (FT(4)), free T(3) (FT(3)), thyroid peroxidase antibody (TPOAb), thyrotrophin receptor antibody (TRAb), and human chorionic gonadotrophin (hCG) tests.(1) The total prevalence of thyrotoxicosis was 9.75% (52/534) in the first trimester and the prevalence of GTT was 7.86%, which accounted for 80.77% of the thyrotoxicosis encountered in this period. A total of 88.89% of the overt GTT showed only elevated FT(3) level. (2) The level of serum hCG increased gradually in the first trimester. The medians of hCG were 25 300, 85 220 and 81 780 IU/L 6, 8 - 10 and 12 weeks after gestation, respectively (P = 0.000). The medians of serum TSH were 1.45, 1.10 and 0.84 mIU/L 6, 8 - 10 and 12 weeks after gestation, respectively (P0.01). (3) When serum hCG was more than 50 000 IU/L, the prevalence of GTT increased obviously. When serum hCG was between 80 000 IU/L and 110 000 IU/L, subclinical GTT increased significantly. When serum hCG was more than 110 000 IU/L, overt GTT increased significantly. Correlation analysis showed that serum hCG was related negatively with TSH (r = -0.402, P = 0.000) and positively with FT(3) (r = 0.165, P = 0.000), but not related with FT(4).The prevalence of GTT is 7.86% in the first trimester and it is the main cause of thyrotoxicosis found in the first trimester, accounting for 80.77% of all the causes. The serological characteristic of overt GTT is mainly the elevation of serum FT(3) level. Serum hCG level is related with the severity of GTT.

To investigate the effect of iodine excess on thyroid follicle epithelial ultrastructure and the relationship between thyroid injury and autoimmune thyroiditis.NOD. H-2(h4) mice and Kunming mice were randomly divided into four groups receiving plain water, 5 fold, 10 fold, and 100 fold excessive iodine water. 4, 8 and 24 weeks after receiving iodine water, the mice were killed. After fixation with osmic acid and dual staining with uranyl chloride and citrate lead, thyroid gland ultrastructure was examined with electron microscopy.Iodine treated NOD. H-2(h4) mice exhibited marked accumulation of peroxisome and secondary lysosomes, apoptosis and necrosis of thyroid epithelial cell, damage of thyroid follicles and lymphocytic infiltration. The observed changes induced by iodine were in a dose dependent way.The oxidative injury on the thyroid epithelial cells induced by iodine excess might be the prerequisite for the creation of autoimmune thyroiditis.

To evaluate the distribution and significance of IgG subclasses of antithyroglobulin antibody in sera from patients with Hashimoto thyroiditis.Sera from 112 patients with Hashimoto thyroiditis were collected and patients were divided into 3 groups, i. e. hypothyroidism, subclinical hypothyroidism and euthyroidism. Antigen specific ELISA was used to detect the distribution of IgG subclasses of antithyroglobulin antibody.The positive rates of IgG subclasses of TgAb were IgG1 90.2%, IgG2 58.0%, IgG3 19.6% and IgG4 87.5% respectively. The mean geometric titers of IgG1 in sera from patients with hypothyroidism and subclinical hypothyroidism were 1: 450.8 and 1: 245.5 respectively, both being significantly higher than that with euthyroidism (1:8.7, P0.01). The mean geometric titers of IgG2 in sera from patients with hypothyroidism and subclinical hypothyroidism were 1: 37.3 and 1: 3.2 respectively, both being also significantly higher than that with euthyroidism (1: 0.2, P0.01 and P0.05 respectively) and that with hypothyroidism was significantly higher than that with subclinical hypothyroidism (P0.05).The distribution of IgG subclasses of antithyroglobulin antibody in sera from patients with Hashimoto thyroiditis was predominantly IgG1, IgG2 and IgG4. High titers of IgG1 and IgG2 implicated the possibility of development from subclinical hypothyroidism to overt hypothyroidism.

To investigate the dynamic changes of serum Th1 and Th2 cytokines in patients with postpartum thyroiditis (PPT) during the first postpartum year.21 patients diagnosed as clinical PPT and 11 healthy postpartum women were enrolled in the study. Blood samples were taken before delivery and every 3 months postpartum for testing serum IFNgamma, IL-2, IL-4 and IL-10, which were measured with ELISA method.In patients with PPT, the detection rate of IFNgamma and IL-2 at 6th month postpartum were 19.0% (4/21) and 14.3% (3/21), respectively, being lower than those before delivery [52.4% (11/21) and 61.9% (13/21), respectively, P0.05]. The detection rate of IL-4 and IL-10 in patients were 71.4% (15/21) and 95.2% (20/21), respectively. A significant raise when compared with that before delivery (61.9%, 13/21) was seen in IL-10 (P0.05). Although Th1 cytokines (IFNgamma, IL-2) declined gradually post-parturition both in healthy postpartum women and PPT patients, yet Th2 cytokines (IL-4, IL-10) showed different tendency in healthy postpartum women and PPT patients. Th2 cytokines declined gradually in healthy postpartum women, while it kept at high level until the 12th month postpartum in the PPT patients.In PPT patients, Th2 cytokines show higher levels after delivery. Th2 cells are dominant and protected thyroids from Th1 cells during the course of PPT; this might be helpful to the recovery from disturbance of thyroid autoimmunity.

To investigate the relationship of thyroid autoantibodies including serum thyroid stimulating antibody (TSAb), thyroid stimulation blocking antibody (TSBAb) and iodine intake with the development and prognosis of Graves' hyperthyroidism.A total of 63 subjects with overt hyperthyroidism were screened out from 3 Chinese rural communities with different iodine intakes at first survey. Serum TSAb, TSBAb, thyrotropin binding inhibitory immunoglobulin (TBII), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb) were detected. The patients were followed up 2 years later. TSAb and TSBAb were measured with recombinant human thyrotropin receptor (rhTSHR)-Chinese hamster ovary cell (rhTSHR-CHO cell) bioassay.At the first survey, the prevalences of positive TSAb, TBII and TSBAb were found in 80.9%, 61.7% and 6.4% of the patients with Graves' disease respectively. TSAb and/or TBII were positive in 91.5% of the patients. The consistent rate of TSAb and TBII was 59.6% in the cases. All indexes mentioned above were higher in the patients than in healthy controls. Positive correlations were found between TSAb and TBII (r = 0.407), TSAb and thyroglobulin (r = 0.301), TSAb and thyroid volume (r = 0.317) respectively. The prevalence of positive TSAb (91.7%) in Graves' patients in iodine excessive area are significantly higher than those in iodine mildly deficient area (66.7%). The positive rates and the titers of TBII, TPOAb and TGAb were not different statistically among the patients in the three communities. At follow-up, the patients with Graves' hyperthyroidism were classified into euthyroid group (G1) and hyperthyroid group (G2) according to their outcomes of the disease. The TSAb titers and the thyroid volume in the cases of G1 decreased significantly, whereas the patients with highly positive TPOAb titers in the first survey and the follow-up were hard to become euthyroid and TSAb may be the secondary factor influencing the thyroid as compared with TPOAb.TSAb is more significant than TBII in diagnosing and predicting the outcomes of Graves' hyperthyroidism. The application of both TSAb and TBII could raise the positive rates of thyrotrophin receptor antibody tests. TSAb, TPOAb titers and thyroid volume were factors influencing the prognosis of Graves' hyperthyroidism.

To investigate the effects of several factors affecting serum thyroglobulin (TG) levels among people aged 14 or more.We selected Panshan with median urinary iodine (MUI) 83.45 micro g/L as a deficient iodine intake community, Zhangwu with MUI 242.85 micro g/L as a sufficient iodine intake community and Huanghua with MUI 650.87 micro g/L as an excessive iodine intake community. Serum TG and thyroid stimulating hormone (TSH) were measured in 3,335 subjects whose thyroglobulin antibody (TGAb) were negative and thyroid volume were examined using B-ultrasound.In the population with MUI of 80 - 650 micro g/L, serum TG levels presented a "V" curve. An elevated serum TG was found in both the communities with deficient iodine intake and excessive iodine intake. The same trend was shown in the groups with different levels of serum TSH. An elevated serum TG was found in both the groups of TSH0.3 mU/L and TSH4.8 mU/L. The serum TG levels was positively correlated with thyroid volume and was higher in female subjects than in male. An increased serum TG was found in subjects of aged 50 in the community with deficient iodine intake.Serum TG level is affected by gender, amount of iodine intake, serum TSH level and thyroid volume.