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PubMed1996

Marked increases in cathepsin B and L activities distinguish papillary carcinoma of the thyroid from normal thyroid or thyroid with non-neoplastic disease.

Cathepsin B (CB) and cathepsin L (CL) are cysteine endopeptidases involved in the processing of thyroglobulin (Tg) in the normal thyroid. As thyroglobulin expression is frequently altered in thyroid carcinomas, we have analyzed 42 human thyroid tissues from 40 patients to study the effect of malignant transformation an the expression of these endopeptidases. Our samples included 18 cases of papillary carcinoma (of which 10 also had matched adjacent normal thyroid tissue), 6 cases of normal thyroid from autopsy patients, 1 case of follicular carcinoma, 2 cases of medullary carcinoma, 2 cases of follicular adenoma, 3 cases of Hashimoto's thyroiditis (HT) and 10 samples from 8 patients with multi-nodular goiter (MNG). Enzyme-specific activities were increased 15-fold for CB and 9-fold for CL in papillary carcinoma compared with normal adjacent thyroid tissue or normal thyroid from autopsies. CB mRNA content was also markedly increased in papillary carcinoma compared with normal thyroid, primarily due to elevated levels of the 2.2-kb CB mRNA transcript. In thyroids with nonneoplastic diseases, including MNG and HT, there was no significant increase in either CB or CL enzyme activities nor CB mRNA levels compared with normal thyroids from non-cancer cases. Immunohistochemical studies on papillary carcinomas revealed increased CB staining in papillary carcinoma cells, with prominent staining close to the basement membranes of many of the neoplastic cells. Our observations suggest that CB and CL enzyme activities are potentially useful new biochemical markers for distinguishing papillary carcinoma of the thyroid from non-neoplastic thyroid disease.

Adenocarcinoma, Follicular↗
PubMed2002

Differential expression of IgG Fc binding protein (FcgammaBP) in human normal thyroid tissue, thyroid adenomas and thyroid carcinomas.

The genetic events involved in thyroid carcinogenesis are still incompletely understood. Several rearrangements and mutations of oncogenes have been implicated in the development of thyroid papillary carcinomas, follicular adenomas and carcinomas. However, none of these molecular alterations is suitable either as a general marker for the diagnosis of thyroid carcinomas or to differentiate between thyroid follicular adenomas and carcinomas. In order to identify new genes with altered expression which could serve as such markers, we analyzed RNA from thyroid tumor and normal tissue using a novel technique called restriction-mediated differential display. Several differentially expressed genes were identified, including the gene for IgG Fc binding protein (FcgammaBP). Differential expression of FcgammaBP was confirmed by quantitative real-time RT-PCR. Our experiments showed that IgG Fc binding protein (FcgammaBP) is differentially expressed in normal thyroid tissue, thyroid adenomas and thyroid carcinomas. While the FcgammaBP gene is constitutively expressed in normal thyroid tissue, its expression is significantly increased in follicular thyroid adenomas and significantly decreased in papillary and follicular thyroid carcinomas. Thus, measurement of the expression levels of FcgammaBP in thyroid biopsies might help to make the otherwise difficult distinction between a thyroid follicular adenoma and a follicular carcinoma.

Adenoma↗
PubMed1993

Autoimmune thyroiditis induced in mice depleted of particular T cell subsets. Characterization of thyroiditis-inducing T cell lines and clones derived from thyroid lesions.

We have previously shown that autoimmune thyroiditis spontaneously develops in T cell-depleted (C57BL/6xC3H/He)F1 mice after adoptive transfer of syngeneic lymphoid cells that have been depleted of CD5bright T lymphocytes. This mouse model was considered to be an instructive model for Hashimoto's thyroiditis in humans, and suggested that CD5dull CD4+ autoreactive T cells are not deleted in normal lymphoid cell populations and induce thyroiditis after elimination of regulatory T cell subsets. In our study, we have established thyroid-derived T cell lines and clones by culturing thyroid-infiltrating lymphocytes with thyroid epithelial cells and syngeneic feeder cells in the presence of exogenous IL-2. Both CD4+ T cells and CD8+ T cells were identified and their CD5 expression was dull or negative. In our report, we focused on CD4+ T cells. Four CD4+ T cell lines and 19 clones were generated and characterized. CD4+ T cell clones derived from F1 hybrid (H-2b/k) mice responded to thyroid Ag in the context of not only class II MHC molecules from both parental strains (I-Ak or I-Ab), but also F1 unique MHC molecules. Thyroglobulin (Tg) was demonstrated to be a major autoantigen of the thyroid for T cell responses, and at least two epitopes of Tg were suggested to be recognized by T cell clones. An additional undefined thyroid component other than Tg was recognized by some T cell clones. Thyroid-derived T cells were all TCR-alpha beta+. Five types of V beta usage (V beta 2, 4, 8.3, 14, and an undefined V beta) were found in CD4+ T cells. Finally, the thyroid lesions could be transferred to syngeneic mice by five distinct groups of CD4+ T cell clones, which were distinguished on the basis of their Ag specificity, MHC restriction, and TCRV beta usage. The considerable heterogeneity of TCRV beta usage of thyroiditis-inducing T cell clones in this study may be attributed to the multiple patterns of their recognition of the thyroid autoantigens. These findings provide important implications for further understanding of organ-specific autoimmune processes induced by depletion of regulatory T cell subsets.

Animals↗
PubMed1992

Thyroid function and thyroid autoimmunity independently modulate serum concentration of soluble interleukin 2 (IL-2) receptor (sIL-2R) in thyroid diseases.

OBJECTIVE: The serum concentration of soluble interleukin-2 receptor (sIL-2R) is a marker of T-lymphocyte activation. Increased circulating sIL-2R has been reported in untreated Graves' disease. This finding has been interpreted as the consequence of the autoimmune activation, but recent data suggest that sIL-2R is directly correlated to thyroid state. The aim of this study was to elucidate the respective roles of autoimmunity and thyroid function in modulating serum sIL-2R. DESIGN AND PATIENTS: sIL-2R was evaluated in 20 normal euthyroid subjects and in a large series of patients with autoimmune and non-autoimmune thyroid disorders in different functional state. MEASUREMENTS: sIL-2R was assayed by a solid-phase monoclonal antibody assisted ELISA method. RESULTS: Serum sIL-2R in normals was 461 +/- 186 U/ml (mean +/- SD). Increased sIL-2R was found in 61 hyperthyroid patients with Graves' disease (1610 +/- 962 U/ml, P < 0.0001) and in 23 with toxic adenoma (1121 +/- 598 U/ml, P < 0.0001). Restoration of euthyroidism lowered to normal sIL-2R in both groups. Serum sIL-2R was higher in euthyroid Graves' disease patients with active than in those with non-active ophthalmopathy. Decreased serum sIL-2R (228 +/- 93 U/ml, P < 0.0001) was found in 30 patients hypothyroid after total thyroidectomy. Highly variable circulating sIL-2R (range 100-1456 U/ml, mean +/- SD: 379 +/- 301 U/ml) was found in 49 patients with hypothyroid Hashimoto's thyroiditis (P = NS vs normals; P < 0.02 vs post-thyroidectomy hypothyroid patients). Treatment with L-thyroxine increased sIL-2R in all thyroidectomized and in the majority of Hashimoto's thyroiditis patients. In individual Hashimoto's thyroiditis patients (mostly with increased serum sIL-2R), L-thyroxine caused a decrease of circulating sIL-2R, sIL-2R was normal in 29 patients with euthyroid Hashimoto's thyroiditis. Both in Graves' disease and in Hashimoto's thyroiditis, no correlation was found between sIL-2R and anti-thyroglobulin, anti-thyroid peroxidase and anti-thyrotrophin-receptor autoantibodies. Highly significant positive correlation between serum thyroid hormones and sIL-2R was found in all study groups. CONCLUSIONS: In thyroid disorders thyroid hormones are the main regulator of serum sIL-2R concentration. The contribution of autoimmune activation may be detected only in some patients with autoimmune hypothyroidism, while in Graves' disease the role of the immune system is masked by the hyperthyroid state.

Adolescent↗
PubMed1990

Thyroid size and function in healthy pregnant women with thyroid autoantibodies. Relation to development of postpartum thyroiditis.

In a study of postpartum thyroiditis, thyroid function and ultrasonically determined thyroid size were evaluated in 36 thyroid autoantibody positive healthy women during pregnancy and the first postpartum year. Twelve women (33%) developed postpartum thyroiditis with permanent thyroid dysfunction in three. However, only one woman had symptoms and needed treatment. The most common type of thyroid dysfunction was a transient hyperthyroid phase as seen in 7 women. A significant increase by 20-30% in mean thyroid volume during pregnancy was demonstrated independent of development of postpartum thyroiditis. We conclude that initial thyroid volume or changes during pregnancy and post partum are not useful indicators of the development of postpartum thyroiditis. The fact that the condition is oligosymptomatic suggests that screening procedures are necessary if one wants to diagnose the earliest phases of postpartum thyroiditis.

Adult↗
PubMed1993

The effects of thyroid-stimulating hormone and thyroid microsomal antibody on thyroid peroxidase activity in human follicular cells: a mini organ culture study.

Thyroid peroxidase (TPO) is an essential enzyme involved in thyroid hormone synthesis and is closely related to the microsomal antigen which is the target of thyroid microsomal antibody. There have been several reports on direct inhibition of peroxidase activity by thyroid microsomal antibody. We prepared a mini organ culture of thyroid glands obtained at operation, and investigated the localization of thyroid peroxidase activity in follicular cells proliferated around the thyroid tissue blocks by electron microscopy. The development of microvilli containing TPO activity on the cell surface facing the culture medium was observed when normal thyroid tissue or Graves' thyroid tissue was incubated with TSH but in the TSH-free group the development of microvilli was poor and TPO activity was very much decreased. After the addition of serum positive for thyroid microsomal antibody, the TPO activity of the microvilli was retained in 4/6 tissue samples, but it disappeared in 2 cases. Our findings suggested that thyroid peroxidase activity is regulated by thyroid stimulating substances such as TSH and by TPO in tissue.

Adolescent↗
PubMed1998

[Non-thyroid illness" or changed thyroid hormone parameter syndrome with non-thyroid illnesses].

BACKGROUND: The multiple effects of systemic illness on thyroid economy are commonly referred to "non-thyroidal illness" (NTI) or "sick euthyroid syndrome". The various aspects of this common syndrome are summarized in this article. STUDIES: Results of the relevant studies published during the past 25 years were evaluated. The influence of the underlying illness and of drug administration was especially emphasized. RESULTS: The most common abnormalities in NTI are 1. the "low-T3 syndrome" due to a decreased T3 generation from T4 by a reduced activity of 5'-deiodinase (a selenoprotein); 2. the "low-T3 low-T4 state", which is associated with a poor prognosis. The low T4-levels are related to a binding inhibitor that displaces T4 from its binding proteins. However, there exists some controversy regarding the character of this binding inhibitor. 3. The high-T4 state is often found in acute psychiatric and liver diseases. The nutritional status of the patients and drugs known to influence thyroid hormone parameters have to be considered when patients with NTI are evaluated. Some difficulties may arise, when there is evidence of coexisting thyroid disease. Here aside from further biochemical evaluation such as thyroid antibodies, thyroid ultrasound and a thyroid scan have to be performed. CONCLUSION: NTI is associated with various alterations in thyroid hormone parameters when no intrinsic thyroid hormone disease exists. The severity of NTI reflects clinical outcome and clinical amelioration is associated with normalization of thyroid hormone parameters. There is no need for specific therapeutic intervention such as the administration of thyroid hormones in patients with the various forms of the NTI-syndrome.

Diagnosis, Differential↗
PubMed1991

Follicular thyroid carcinoma masquerading as subacute thyroiditis. Diagnosis using ultrasonography and radionuclide thyroid angiography.

The rare presentation of a follicular thyroid carcinoma mimicking the clinical and radionuclide features of subacute thyroiditis is described. Granulomatous thyroiditis was initially suspected on the clinical basis of acute onset of a hard, tender right lobe thyroid enlargement with associated systemic symptoms, modest elevation of thyroid hormone levels and suppressed thyroid RAIU. Fine needle aspiration cytology specimens were unsatisfactory for characterization. Three weeks later the thyroid RAIU was normal. The thyroid enlargement persisted, now being clearly visualized as a hypofunctional nodule on scintiscan. Repeat fine needle aspiration cytology was suggestive of acinar proliferation with hyperfunction. Ultrasonography revealed a solid nodule with a peripheral sonolucent halo. Radionuclide angiography showed intense arterial flow of Tc-99m pertechnetate through the right lobe thyroid enlargement suggestive of malignant thyroid pathology. Surgical excision and histopathological examination revealed a follicular carcinoma involving the right lobe. The possibility of carcinomatous involvement should be considered in those patients where initially tender thyroid nodularity persists longer than expected for a benign inflammatory disease, careful follow-up and relevant investigations being necessary to confirm the diagnosis.

Adenocarcinoma↗
PubMed1998

Outcome of thyroid function in Graves' patients treated with radioiodine: role of thyroid-stimulating and thyrotropin-blocking antibodies and of radioiodine-induced thyroid damage.

UNLABELLED: We investigated the interrelationship and the influence of thyroid-stimulating antibodies (TSAb), TSH-blocking antibodies (TSHBAb), and of radioiodine (131I)-induced thyroid damage in the early (within 1 yr) outcome of thyroid function in hyperthyroid patients with Graves' disease (GD) treated with 131I. TSAb, TSHBAb, and ultrasound thyroid volume (as an index of thyroid damage) were simultaneously measured before and at 1, 3, 6, and 12 months after 131I in 31 GD patients. One year after radioiodine, 9.7% of patients were hyperthyroid (Hyper-group), requiring methimazole; 12.9% were euthyroid (Eu-group); and 77.4% were hypothyroid (Hypo-group). Pretreatment thyroid volume in the Eu-group and Hyper-group was significantly greater (P = 0.009) than in the Hypo-group. Pre-131I TSAb levels were higher in the Hyper-group vs. the Hypo-group (P = 0.01) or the Eu-group (P = 0.03). A significant post-131I increase in TSAb levels occurred in 66% of patients developing hypothyroidism but not in those remaining hyperthyroid. After 131I, TSHBAb appeared in 7 patients, in all but one associated with high levels of TSAb. One year after radioiodine: 1) the mean percent reduction in thyroid volume was greater in the Hypo-group (80.7%) or the Eu-group (83.5%) than in the Hyper-group (35.7%) (P = 0.007 and 0.0033 respectively); 2) hypothyroid patients had smaller (P = 0.0058) post-131I thyroids than hyperthyroid patients; and 3) TSAb were still elevated in 75% hypothyroid patients, but all of them had a thyroid volume < or = 8 mL, indicating major postradioiodine gland damage. IN CONCLUSION: 1) the early outcome of thyroid function after 131I for GD is mainly related to pretreatment thyroid volume and to the degree of its reduction after therapy; 2) high TSAb levels before 131I are associated with a relative resistance to therapy; 3) a postradioiodine increase in TSAb levels is related to the development of hypothyroidism; and 4) the concomitant appearance of TSHBAb and disappearance of TSAb are not frequent after 131I and play a role in the development of early postradioiodine hypothyroidism only in a minority of patients.

Adult↗
PubMed1989

[Changes in anti-thyroid hormone and anti-thyroglobulin antibodies during thyroid hormone(s) or prednisolone treatments in 3 cases of Hashimoto's thyroiditis].

We have experienced 3 cases of Hashimoto's thyroiditis with anti-thyroid hormone antibodies. Changes in titers of anti-thyroglobulin(Tg) and anti-thyroid hormone antibodies during 6 year (Cases 1 and 2) and 7 year (Case 3) observation periods were examined in each case. Cases 1 (13-year-old) and 2 (10-year-old) are sisters with hypothyroidism whose chief complaint was short stature. They were diagnosed as having Hashimoto's thyroiditis by needle biopsy of the thyroid gland. Presence of anti-thyroid hormone antibodies were found in the sera of both cases (Case 1: anti-thyroxine(T4) antibodies, Case 2: anti-triiodothyronine(T3) antibodies). They were treated with synthetic T4 or combined therapy of T3 and T4, and serial sera obtained during the 6 year treatment period were tested for the titers of anti-Tg and anti-thyroid hormone antibodies. Case 3 (23-year-old female), who was diagnosed as having Hashimoto's thyroiditis associated with systemic lupus erythematosus (SLE) and Sjögren's syndrome had been treated with prednisolone(PSL) for 8 years. After one year of strating the treatment, she was found to have unusually low serum T3 measured by radioimmunoassay. Further examination revealed the presence of anti-T3 antibodies in her serum. Serial sera obtained during the 7 year observation period were tested for the titers of anti-Tg and anti-T3 antibodies. In cases 1 and 2, replacement therapy with thyroid hormone resulted in the decrease of titers of anti-thyroid hormone antibodies. In addition, increase in serum TSH concentrations was accompanied with increased titers of anti-Tg and anti-thyroid hormone antibodies in all 3 cases. The exact mechanism for it is not clear.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2002

Objective evidence of decreased salivary function in patients with autoimmune thyroiditis (chronic thyroiditis, Hashimoto's thyroiditis).

Impaired salivary flow is found in Sjögren's syndrome, which is a common, chronic, autoimmune, inflammatory connective tissue disease, mainly affecting the exocrine glands. Histopathologically, lymphocytic infiltrations of the salivary glands are found in Sjögren's syndrome that are similar to those of the thyroid gland in autoimmune thyroiditis (chronic thyroiditis, Hashimoto's thyroiditis). To test this hypothesis by Daniels et al ., salivary function was measured by quantitative salivary scintigraphy in autoimmune thyroiditis patients, as well as in age- and sex-matched controls. Forty patients, each with a history of autoimmune thyroiditis of over 10 years, and 61 healthy controls were enrolled in the study. All of the 40 autoimmune thyroiditis patients had good blood sugar control. None presented autonomic neuropathy. They were separated into two subgroups: patient group 1, 20 patients with xerostomia; patient group 2, 20 patients without xerostomia. Two control groups of healthy subjects were included for comparison: control group 1, 36 subjects without xerostomia; control group 2, 25 subjects with xerostomia. After intravenous injection of 5 mCi (99m)Tc-pertechnetate, sequential images at 1 min per frame were acquired for 30 min. The first and 15th minute uptake ratios (URs) were calculated from the tracer uptakes in the four major salivary glands relative to the background regions of interest (ROIs). Saliva excretion was stimulated by one tablet of 200 mg ascorbic acid given orally 15 min after injection of the tracer. The maximal excretion ratios (ERs) of the four major salivary glands after sialagogue stimulation were calculated. Impaired salivary function, represented by significantly decreased UR and ER values, in autoimmune thyroiditis patients with xerostomia was demonstrated in this study. Significantly poorer salivary function was found in autoimmune thyroiditis patients with xerostomia, when compared with autoimmune thyroiditis patients without xerostomia and healthy controls with or without xerostomia, via objective and quantitative salivary scintigraphy. However, a larger series of autoimmune thyroiditis patients is necessary to confirm our findings.

Adult↗
PubMed2002

Mice with a mutation in the thyroid hormone receptor beta gene spontaneously develop thyroid carcinoma: a mouse model of thyroid carcinogenesis.

The molecular genetic basis of thyroid carcinogenesis is not well understood. Most of the existing models of thyroid cancer only rarely show metastases, and this has limited progress in the understanding of the molecular events in thyroid cancer invasion and metastasis. We have recently generated a mutant mouse by introducing a dominant negative mutant thyroid hormone nuclear receptor gene, TRbetaPV, into the TRbeta gene locus. In this TRbetaPV mouse, the regulation of the thyroid-pituitary axis is disrupted, leading to a mouse with high levels of circulating thyroid-stimulating hormone and extensive hyperplasia of follicular epithelium within the thyroid. As TRbeta(PV/PV) mice, but not TRbeta(PV/+) mice, aged, metastatic thyroid carcinoma developed. Histologic evaluation of thyroids of 5-14-month-old mice showed capsular invasion (91%), vascular invasion (74%), anaplasia (35%), and metastasis to the lung and heart (30%). Previous models of thyroid cancer have focused on genes that control initial carcinogenesis, but this model provides an unusual opportunity to study the alterations in gene regulation that occur with clinically relevant changes during progression and metastasis in a predictable fashion.

Anaplasia↗
PubMed1994

Studies of human thyroid xenografts from Hashimoto's thyroiditis in severe combined immunodeficient (SCID) mice: detection of thyroid stimulation-blocking antibody.

Human thyroid xenografts from 7 patients with Hashimoto's thyroiditis (HT) and 3 normal persons (N) were xenografted into severe combined immunodeficient (SCID) mice to study the intrathyroidal lymphocytes that were expected to survive in these animals. Human IgG was detected in all mice engrafted with HT thyroid tissue peaking at 6-10 weeks after xenografting. Thyroperoxidase-antibody (TPO-Ab) was also detected in all mice with HT thyroid grafts peaking at 4-6 weeks after xenografting, reaching up to 44% of donors' original concentrations. In contrast, maximal thyroglobulin (Tg)-Ab production in some SCID mice with HT thyroid grafts was higher than the donors' original level, and was detectable in mice with thyroid grafts from Tg-Ab-negative HT donors. Thyroid stimulation-blocking antibody (TSBAb) was found in 2 mice with thyroid xenografts from 1 HT patient whose original serum TSBAb and thyrotropin-binding inhibitor immunoglobulin (TBII) had been positive; the maximal TSBAb level in SCID mice exceeded the donor's original level. TSBAb production in SCID mice reached its peak at 10 weeks after xenografting, i.e., later than that of thyroid-stimulating antibody (TSAb) observed in our recent report, suggesting the existence of distinct intrathyroidal B cell autoreactive clones of different life span responsible for secreting TSAb or TSBAb. When autologous peripheral blood mononuclear cells (PBMC) were engrafted alone (without thyroid tissue), TSBAb was undetectable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Influence of thyroxine treatment on thyroid size and anti-thyroid peroxidase antibodies in Hashimoto's thyroiditis.

OBJECTIVE: It has been postulated that a decrease in thyroid size can be achieved by thyroxine treatment in patients with goitrous Hashimoto's thyroiditis but no objective data are available. We have therefore investigated the influence of thyroxine treatment on ultrasonically determined thyroid size. We also measured serum antithyroid peroxidase antibodies. DESIGN: Consecutive patients with goitrous Hashimoto's thyroiditis was studied. PATIENTS: Thirteen women participated; all had goitrous thyroiditis. TREATMENT: To render them euthyroid thyroxine was given for 24 months. MEASUREMENTS: Thyroid size was measured ultrasonically and antithyroid peroxidase antibodies were measured using a commercial radioimmunological method. RESULT: Concomitant with the gradual increase in serum free thyroxine and free triiodothyronine index values and a fall in serum thyrotrophin level, a gradual decrease in thyroid volume from 50.4 +/- 6.8 ml (mean +/- SEM) to 34.1 +/- 5.7 ml (32%), P less than 0.001 was demonstrated. Antithyroid peroxidase antibodies were present in high concentrations in all subjects but the mean serum level was not significantly changed at 24 months after initiation of treatment. CONCLUSION: A clinically significant reduction in thyroid volume related to normalization of thyroid function but unrelated to changes in antithyroid peroxidase antibody can be achieved during L-thyroxine treatment of hypothyroid goitrous Hashimoto's thyroiditis.

Adult↗
PubMed1993

Dose-response relationships for radiation-induced thyroid cancer and thyroid nodules: evidence for the prolonged effects of radiation on the thyroid.

The risk of developing thyroid cancer and other thyroid neoplasms after radiation exposure is well known, but specific modifiers of the dose-response relationship are not. We have identified 4296 subjects who received treatment before their sixteenth birthday with orthovoltage radiation for benign conditions in the head and neck area. Individual thyroid dose estimates were calculated for 3843 subjects. Of the 2634 subjects who have been found, 1043 have developed thyroid nodules of all types, and 309 have developed thyroid cancer. The radiation dose-response relationship was consistent with a linear excess relative risk model for thyroid cancer and thyroid nodules within the range of observed doses. Women developed thyroid cancer and thyroid nodules at a higher rate, but the slopes of the dose-response curves were the same for men and women. Age at radiation exposure was a significant factor of the risk, with a lower age at exposure associated with a higher risk. To determine the effect of the wide publicity and our screening program, which began in 1974, we compared the dose-response relationship for cases diagnosed before and after 1974. The overall rates increased dramatically after 1974, but the estimates of the slopes of the dose-response curves were not statistically different. The slope of the dose-response curve for thyroid neoplasms appears to have reached a maximum 25-29 yr after radiation exposure, but the dose response continued to be elevated at the end of follow-up. These data are consistent with the tumorigenic effects of radiation lasting at least 40 yr.

Adult↗
PubMed1983

Lack of refractoriness to stimulation with long acting thyroid stimulator of thyroid hormone synthesis and thyroid hormone secretion in mice in vivo.

The present study was undertaken to examine whether long acting thyroid stimulator (LATS) induces refractoriness of thyroid hormone synthesis and thyroid hormone secretion to the stimulator in vivo. Male DDY mice fed with a low iodine diet and given 5 micrograms/ml of triiodothyronine (T3) in drinking water and libitum for 4 days were injected with 0.025 ml of LATS positive serum (1000%/0.25 ml in rhe McKenzie bioassay) ip every 24 h for 9 days. Groups of 5 mice were sacrificed before and 1, 3, 5, 7 and 9 days after the first injection of LATS for the determinations of serum thyroxine (T4) concentrations, the 1 h thyroid 131I uptake and thyroid weight. Control mice were injected with LATS negative pooled normal sera. Serum T4 concentrations elevated significantly 24 h after the 3rd injection of LATS and remained elevated until the end of the experiment. One hour thyroid 131I uptake elevated about 3-fold 24 h after the first injection of LATS. It further increased 24 h after the 3rd injection of LATS to 10-fold of the value for control animals and stayed elevated at this same level for the remainder of the study. These results indicate that stimulating effects of LATS on thyroid hormone synthesis assessed by thyroid 131I uptake and thyroid hormone secretion assessed by serum T4 concentrations were not diminished by the prior administration of the stimulator. These findings suggest that LATS does not induce refractoriness of either thyroid hormone synthesis or thy roid hormone secretion to the stimulator in mide in vivo.

Animals↗
PubMed2002

The cost effectiveness of dual phase 201Tl thyroid scan in detecting thyroid cancer for evaluating thyroid nodules with equivocal fine-needle aspiration results: the preliminary Taiwanese experience.

The purposes of this study were to assess the helpfulness of dual phase 201Tl thyroid scan for differentiating malignant from benign thyroid lesions in cases of thyroid nodules with equivocal fine-needle aspiration (FNA) biopsy results. In addition, for thyroid nodules with equivocal FNA biopsy results, we try to make a decision analysis model compared the FNA biopsy alone strategy (strategy A) with decision strategy for the assistance of dual phase 201Tl thyroid scan (strategy B) before diagnostic thyroidectomy as thyroid cancer evaluation strategies for hypothetical cohorts of estimated 17,280-29,160 Taiwanese patients/per year with equivocal FNA biopsy results. Based on the findings of surgical histopathology, dual phase 201Tl thyroid scan sensitivity, specificity, and accuracy were 100%, 90%, and 96%, respectively, in cases of 27 thyroid nodules with equivocal FNA biopsy results. In cost effectiveness analysis, the strategy B showed a cost saving of 16,340,480-27,574,560 US dollars in unnecessary diagnostic thyroidectomy cost. The total cost of strategy B showed a cost saving of 13,932,232-23,520,564 US dollars than that of strategy A. The preliminary data indicate that dual phase 201Tl thyroid scan can save the cost of unnecessary diagnostic thyroidectomy in Taiwanese patients with equivocal FNA biopsy results. In addition, we may provide a noninvasive diagnostic method--dual phase 201Tl thyroid scan, as the first priority for Taiwanese patients with equivocal FNA biopsy before diagnostic thyroidectomy under the coverage of the national health insurance system in Taiwan.

Adolescent↗
PubMed1994

Effects of thyroid status on thyroid autoimmunity expression in euthyroid and hypothyroid patients with Hashimoto's thyroiditis.

OBJECTIVE: In patients with hypothyroid goitrous Hashimoto's thyroiditis, the recovery from hypothyroidism seems to be due to a spontaneous decrease of antibodies (Ab) to the TSH-receptor (R). In contrast, in patients with Graves' disease made euthyroid by antithyroid drug therapy, the suppression of TSH secretion by thyroid hormone during antithyroid drug treatment decreases the production of Ab to TSH-R. We investigated in patients with initially euthyroid or hypothyroid goitrous Hashimoto's thyroiditis the relationships between thyroid status and the serum TSH-R, peroxidase (TPO) and thyroglobulin (Tg) Ab concentrations in untreated or L-thyroxine (T4) treated patients. PATIENTS: A prospective study of 174 consecutive patients, referred with goitrous Hashimoto's disease in an initially euthyroid (group I, n = 78) or hypothyroid (group II, n = 96) state. The patients with positive (> or = 7%) TSH-RAb (group I, n = 18; group II, n = 22) were reinvestigated 12 months after the initiation of L-T4 therapy. After which, (1) L-T4 was continued and an evaluation performed 2 months later (i.e. 14 months after L-T4 initiation) in 9 patients of group I and in 11 patients of group II or (2) L-T4 was withdrawn and an evaluation performed 2 months later in 9 patients of group I and in 11 patients of group II. MEASUREMENTS: Measurements of basal plasma TSH, free T4 (FT4) and total T3 and serum TSH-R, TPO and TgAb. RESULTS: The prevalence of positive TSH-RAb levels did not differ between group I (23.1%) and group II (22.9%). However, the mean TSH-RAb level in group I (9.4 +/- 0.4%) was lower (P < 0.01) than in group II (11.6 +/- 0.5%). In the patients with positive TSH-R Ab, (1) the prevalences of positive TSH-RAb decreased (P < 0.001) under L-T4 therapy (group I = 22.2%, group II = 21.2%) and increased again (P < 0.01) 2 months after L-T4 cessation (group I = 77.7%, group II = 63.6%) to reach lower levels (group I, P < 0.05; group II, P < 0.01) than those obtained prior to L-T4 treatment. Statistical analysis of TSH levels through the course of the study confirmed these results. (2) In contrast to the variations of the mean TgAb values, the variations of the mean TPOAb levels in each group were in good agreement with those of TSH-RAb through the course of the study. (3) There were significant correlations between some parameters of thyroid status and both TSH-RAb (TSH, r = 0.43, P < 0.001; FT4, r = -0.35, P < 0.01) and TPOAb (TSH, r = 0.42, P < 0.001; FT4, r = -0.31; P < 0.01) levels. In contrast, no correlations were found between thyroid status and TgAb values. CONCLUSIONS: This study demonstrates that thyroid status can modulate thyroid autoimmunity expression, such as TSH-RAb and TPOAb, in patients with euthyroid or hypothyroid goitrous Hashimoto's thyroiditis. Similar results have been reported in patients with Graves' disease made euthyroid by the administration of thyroid hormone during antithyroid drug treatment.

Adult↗