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At least 55 records · Page 3Linked to original sources
PubMed1999

Structure of the thyroid gland, serum thyroid hormones, and the reproductive cycle of the Atlantic stingray, Dasyatis sabina.

This study examines the role of the thyroid gland in the control of reproduction in the viviparous Atlantic stingray, Dasyatis sabina. Thyroid activity in individuals in different reproductive stages was assessed both by microscopic examination of the gland, and by analysis of circulating levels of thyroid hormones from the same individuals. The thyroid gland is a cylindric organ, embedded in a connective tissue capsule, and composed of follicles, i.e., monolayer spheres of thyroid epithelial cells. Stingray follicular cells possess several characteristic features, namely apical cilia and a well-developed endoplasmic reticulum. Cells vary in size and shape, according to the activity of the gland. No structural differences were observed between the thyroid glands of the two sexes. Both thyroid hormones, triiodothyronine, [T(3)], and thyroxine, [T(4)], were detected in the serum of all animals examined. Levels ranged from 1.3-2.6 microg/100 ml for total T(4), and from 1.2-2.6 ng/ml for total T(3). The T(4) levels did not vary significantly in any group. Immature individuals and females undergoing oogenesis had the lowest levels of circulating T(3) and mature females from ovulation throughout gestation had high thyroid gland activity and high levels of circulating T(3). J. Exp. Zool. 284:505-516, 1999.

Animals↗
PubMed1984

Expression of intermediate filament proteins in thyroid gland and thyroid tumors.

The presence of intermediate filament proteins of cytokeratin/prekeratin type and vimentin type was evaluated in non-neoplastic thyroid glands and in different types of thyroid neoplasms. Follicular epithelium of both normal and goitrous thyroids showed a strong reaction with anticytokeratin antibodies that widely cross-react with various simple epithelia. On the other hand, in normal thyroid, there were only occasionally (in one of 12 cases) solitary cells reacting with antibodies to epidermal prekeratin. In nodular goiters, such cells were often seen (eight of 18), especially among the lining cells of cysts, and in chronic thyroiditis in all (12 of 12) cases. Only the stromal cells and intraluminal macrophages reacted with antibodies to vimentin. Neoplastic cells of papillary carcinomas showed a positive staining reaction both with antibodies to cytokeratins and to epidermal prekeratin. Follicular carcinoma cells, although positive for cytokeratins, could generally not be stained with antibodies to epidermal prekeratin. Medullary carcinoma cells also showed cytokeratin positivity and, only occasionally, positivity for epidermal prekeratin. Anaplastic carcinomas were also reactive with antibodies to cytokeratin but, for the most part, were negative for epidermal prekeratin. Interestingly, some neoplastic cells of all types of thyroid carcinomas also appeared to contain vimentin, as shown with both polyclonal and monoclonal antivimentin antibodies. In contrast to carcinomas, the intermediate filaments of thyroid sarcomas and lymphomas were only of vimentin type. Furthermore, it was found that the papillary structures in benign goiters were only reactive with cytokeratin antibodies and lacked, in contrast to papillary carcinomas, epidermal prekeratin-like immunoreactivity. Hence, the analysis of intermediate filament proteins of thyroid tumors can be utilized to differentiate between papillary and follicular carcinomas and between benign and malignant papillary lesions as well as between anaplastic thyroid carcinomas and sarcomas or lymphomas.

Adenocarcinoma↗
PubMed1984

Short and long term effects of radioiodine treatment on the iodine content of the thyroid gland.

Thyroid iodine content (TIC) was measured in nine patients with hyperthyroid Graves' disease for 5-26 months after treatment with 131I (100-125 muCi/g tissue). In all patients, TIC decreased; in eight patients it became undetectable within 5 +/- 3 (SD) months. This fall was parallel to those of serum T3 and T4 levels and was not prevented by the administration of large doses of stable iodine. In four patients, this decrease was irreversible and they became clinically hypothyroid. In the five other patients, it was partly reversible: the secondary increase of TIC was parallel to those of serum T3 and T4 and to a decrease in TSH levels. These data suggest that during the months after 131I treatment, determination of TIC may help to distinguish transient from irreversible hypothyroidism. The late effects of 131I were studied in 38 patients who had been treated for hyperthyroid Graves' disease from 1.5-22 yr previously. The 16 patients who, at the time of examination, were euthyroid with normal serum TSH levels (less than 8 microU/ml) had a TIC [3.2 +/- 3 (SD) mg] significantly lower than that of 10 euthyroid patients previously treated only with antithyroid drug therapy (16.7 +/- 8.2 mg). A significant negative correlation was found between log basal TSH and log TIC (r = 0.61, P less than 0.001) and a positive correlation between log T4 and log TIC (r = 0.56, P less than 0.002). The T3/T4 ratio in patients with undetectable TIC (19.9 +/- 7.9) was higher than that of the other patients (14.6 +/- 3.2) (P = 0.02, Wilcoxon test). This hormonal profile was not modified by iodide supplementation, which increased TIC only transiently. The turnover of thyroid iodine was accelerated, which appeared to be the consequence of a small thyroid functional mass and of hyperstimulation by TSH.

Graves Disease↗
PubMed1984

Expression of laminin in thyroid gland and thyroid tumors: an immunohistologic study.

Thirty-five thyroid tumors and four normal thyroids were immunohistochemically investigated for the presence of laminin, a major basement membrane component. The thyroid follicles in normal tissues and in nodular goiters were surrounded by a continuous rim of laminin positivity, as were also the papillae of papillary carcinomas. Follicular adenomas and well-differentiated follicular carcinomas also showed laminin positivity around most of the follicles. Anaplastic thyroid carcinoma lacking a distinct compartmentalization of tumor cells also lacked pericellular laminin. However, in contrast to all other thyroid tumors, an intense laminin positivity was found in scattered tumor cells of anaplastic carcinomas. Laminin positivity is thus a feature reflecting the differentiation level of thyroid tumors, but, unlike most other carcinomas, differentiated thyroid tumors have basal laminae surrounding the differentiated structural units.

Adenoma↗
PubMed2006

Cyclin D1 protein expression in human thyroid gland and thyroid cancer.

Cell cycle progression is facilitated by cyclin dependent kinases (CDKs) that are activated by cyclins, including Cyclin D1 and inhibited by CDK inhibitors. Evidence of the involvement of cyclin gene alterations and over expression of various cyclins in human cancer is growing. The role of Cyclin D1 in malignant progression of papillary carcinomas of the thyroid has yet to be established. We therefore studied the expression of Cyclin D1 protein in thyroid carcinomas of young Kuwaiti patients (36 cases of conventional papillary thyroid carcinoma, 12 cases of its follicular variant, one case of tall cell thyroid carcinoma and one case of medullary carcinoma) using immunohistochemistry. In 23 patients (46%) circumscribed areas of cells were detected that showed a distinct to strong nuclear staining for immunoreactive Cyclin D1 whereas the remaining bulk of the carcinoma cells were negative or only showed a slight cytoplasmic staining. None of the tested clinical or path histological parameters showed a statistically significant correlation with the focal immunostaining. This does not rule out that the detected foci with positive nuclear Cyclin D1 immunostaining are areas where a progressive transformation to a more malignant phenotype occurs which eventually leading to lymph node and distant metastases.

Adenocarcinoma, Follicular↗
PubMed1989

Influence of rifampicin on thyroid gland volume, thyroid hormones, and antipyrine metabolism.

The influence of rifampicin (450 mg/day for 28 days) on the hepatic microsomal enzymes and thyroid function variables were investigated in 13 healthy male volunteers. After 14 and 28 days of treatment a significant increase in median thyroid volume (determined ultrasonically) was demonstrated (20 ml, range 13-28 before; 26 ml, range 18-48 at day 14, and 24 ml, range 17-40 at day 28) (p less than 0.01). A significant decrease in median serum free T4 index levels was seen (94.1 arbitrary units, range 80.1-123.4 before treatment; 86.8, range 71.7-102.0 at day 14, and 85.3, range 65.5-131.3 at day 28) (p less than 0.01). Serum T4, T3, T3 resin uptake, free T3 index and TSH levels were not significantly altered. Hepatic microsomal enzyme activity assessed by antipyrine clearance was significantly increased (approximately by 85%) at day 14 and 28, whereafter it normalized. The study supports the hypothesis that the increase in thyroid volume after treatment with rifampicin and other hepatic enzyme system inducers (e.g. phenytoin and carbamazepine) is a compensatory mechanism caused by an increased hepatic degradation of thyroid hormones.

Adult↗
PubMed1991

[Evaluation of thyroid gland scintigraphy and thyroid gland ultrasonography from the surgical viewpoint].

The results of thyroid ultrasound and scanning on 251 patients have been reviewed in regard of the postoperative histological findings. Both procedures (thyroid ultrasound and scanning) cannot predict the histology. But with ultrasound adenomas of the thyroid for example could be localized in 93%, with isotope scanning only in 74%. Merely 2% of cold nodules with decreased or mixed sonographic pattern have been malignant. Ultrasonography is extremely helpful for the surgeon in his operative planning.

Adenocarcinoma↗