Experimental autoimmune thyroiditis induced by a 5-10-kDa tryptic fragment from porcine thyroglobulin.

Monoclonal autoantibodies obtained using the native porcine thyroglobulin (Tg) molecule for immunization were shown to react against a defined epitope of the Tg molecule. Its biochemical characterization was undertaken, using trypsin treatment of Tg, followed by gel filtration, affinity chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and high pressure liquid chromatography analysis. Immunoreactivity tested by immunoblotting with appropriate monoclonal anti-Tg antibody allowed the detection of one peptide fragment of 5-10 kDa, after limited proteolysis with trypsin.

Functional role in self reactivity for Ia antigens on murine synovial cells.

Cultures of synovial cells from normal CBA mice were established after collagenase treatment of synovial tissue collected from the knee joint. Morphological studies using light and electron microscopy have shown that confluent monolayers are composed of 90% triangular or stellate dendritic cells with numerous microvilli and 5% secreting cells containing many dense granules. Less than 5% contaminating cells, such as fibroblasts or macrophages, are present.

Forskolin stimulates cAMP production and the onset of the functional differentiation in the fetal rat thyroid in vitro.

Forskolin, a diterpen stimulating the adenylcyclase induces in vitro an accumulation of cAMP in thyroid glands explanted from 17 day-old rat fetuses. Thyroid glands from 15 day-old fetuses exposed to forskolin exhibit, within 24 hr, an active folliculogenesis and 125I fixation in follicular cavities. The results indicate that cAMP probably activates the onset of both morphological and physiological maturation in the fetal rat thyroid.

Syngeneic sensitization of mouse lymphocytes on monolayers of thyroid epithelial cells (TEC). VIII: Gamma interferon induced Ia antigen expression on TEC cultures.

We previously reported that the expression of Ia antigens on cultured monolayers of murine thyroid epithelial cells (TEC) occurred with a particular distribution exclusively on the basal part of the cultured thyroid cells, while class I antigens of the major histocompatibility complex (MHC) and thyroglobulin (Tg) are only detected on the apical surface. It appears that, 24 to 48 h after the deposition of syngeneic lymphocytes, Ia antigens are expressed on the apical side of cultured TEC, i.e.

Monoclonal human thyroid cell line GEJ expressing human thyrotropin receptors.

By using the hybridoma technology, a monoclonal human thyroid cell line was obtained by fusing fresh normal human thyroid cells with a human lymphoblastoid cell line. The resultant cell line, called GEJ, has been selected for its expression of thyrotropin (TSH) receptors and has morphological and functional characteristics of normal human thyroid cells. In the presence or absence of human TSH, the GEJ cell line accumulates iodide, produces thyroid hormones, expresses thyroid membrane antigens, and binds approximately equal to 600 molecules of TSH per cell.

TSH stimulation of iodine organification in early foetal rat thyroid in vitro.

Thyroid glands from 15 day-old rat foetuses were incubated in Eagle's medium containing Na 125I and supplemented, or not, with TSH for 4 or 24 hours. Electron microscopic radioautographic study shows silver grains mainly in follicular cavities only in the thyroids submitted to TSH during 24 hr. A functional differentiation must therefore take place in thyroid cells under TSH stimulation.

Expression of H-2 antigens and thyroglobulin (Tg) on freshly dissociated and in vitro cultured monolayers of mouse thyroid epithelial cells (TEC).

The expression of the major histocompatibility complex antigens (K, D, and Ia) and thyroglobulin was studied on both freshly dissociated and in vitro cultured murine thyroid cells. Methods used for antigen detection included direct cytotoxicity, fluorescence and electron microscopic studies. Results obtained showed that the K-end, the D-end and thyroglobulin antigens are expressed exclusively on the apical cell surface of thyroid epithelial cells, while Ia antigens are found on the basal part of the cell.

Thyroid follicular morphogenesis mechanism: organ culture of the fetal gland as an experimental approach.

The morphological and physiological changes induced by organ culture and thyroid-stimulating hormone (TSH) stimulation in the rat fetal thyroid gland were studied. Organ culture increased Golgi activity which was further enhanced by TSH, subsequently facilitating the formation of intracellular lumina. TSH also raised the intracellular cAMP level.

Basement membrane maintenance in cultures of isolated thyroid follicles.

Follicles from adult rat thyroid glands were isolated by digestion with collagenase followed by sieving. Electron microscopic studies have shown that basement membrane was present around each one of the isolated follicles. Follicles were cultured in vitro with or without thyrotropin and fibronectin.

Thyrotropin effects on vesicle transfer and thyroid follicle morphogenesis: a stereological study in the rat.

Incubation in a culture medium with and without TSH of 16 day-old foetal thyroid glands induces hypertrophy of the Golgi apparatus which may be correlated with a considerable increase in the number of secretory vesicles. A stereological study performed during the first 6 hr of incubation showed that: vesicle secretion was biphasic; vesicle secretion was heterogeneous with two different populations of vesicles; When TSH (20 mU and 80 mU) was added to the medium, the volume density of the follicular lumina increased; at least during the first 6 hr TSH seemed to be necessary to the formation of follicular lumina.

Syngeneic sensitization of mouse lymphocytes on monolayers of thyroid epithelial cells. III. Induction of thyroiditis by thyroid-sensitized T lymphoblasts.

During in vitro sensitization of CBA spleen lymphocytes on syngeneic monolayers of either thyroid epithelial cells (TEC) or fibroblasts, stimulation occurs, as assessed by thymidine incorporation and lymphoblast generation. When lymphoblasts generated on syngeneic TEC are injected either into thyroid lobes of intact CBA recipients or i.v.

[Differences in the distribution of class I and II antigens of the major histocompatibility complex on the surface of cultured epithelial cells of the mouse thyroid].

From day 9 to 15 of Thyroid Epithelial Cell (TEC) culture the expression of MHC antigens (K, D and Ia) was studied. Methods used for antigen detection included direct cytotoxicity in the presence of rabbit complement and electron microscopy using goat anti-mouse peroxidase-labeled Fab fragments. Results obtained showed that the K and D end-coded MHC antigens (class I) are exclusively expressed on the apical cell surface of TEC while Ia antigens (class II) are only found on the basal part of the cell.

[Benign pseudo-tumoral lymphoid hyperplasia with massive Destombes-Rosai-Dorfman histiocytosis].

The authors report one case of sinus histiocytosis with massive lymphadenopathy which occurred in a 70 years old woman. They remind the main features of this pseudolymphomatous benign disorder with three key microscopic findings : massive sinus histiocytosis, lymphophagocytosis, proliferation of mature plasma cells. There is no effective therapy and nothing definite about the etiology.

Development of the thyroid gland in the rat fetus in vivo. An ultrastructural and radioautographic study.

A study of the differentiation of the thyroid follicles was carried out in rat fetuses between day 14 of pregnancy, when cellular polarization begins and day 18, when completely formed follicular lumina are differentiated. After day 18, only the shape and the size of the lumina undergo modifications. The mechanism of folliculogenesis involves the participation of several structures.

Critical study of endogenous peroxidase activity: its role in the morphofunctional setting of the thyroid follicle in the rat fetus.

Endogenous peroxidase is associated with thyroglobulin iodination. It first appears at 17 day of pregnancy in rat fetal thyroid and seems to be synthesized within the perinuclear cistern and the rough endoplasmic reticulum. Then, the enzyme is transferred by vesicles up to the follicular lumen where thyroglobulin iodination takes place.

Biosynthesis of the basal lamina as a result of interaction between thyroid and mesenchymal cells in culture.

Porcine thyroid cells were cultured alone or in mixed cultures with mesenchymal cells. The formation of a basal lamina in vitro was investigated ultrastructurally. Follicular reassociation of thyroid cells occurred in both types of culture; however, it was followed by formation of the basal lamina only when mesenchymal cells were present.

Polarity of three-dimensional structures derived from isolated hog thyroid cells in primary culture.

When cultured in polystyrene dishes subjected to previous treatment and supplied with a serum-containing medium, hog thyroid cells form monolayers displaying dome-like arrangements after three to four days. Cells involved in formation of "domes" are morphologically polarized; the apical microvilli of these cells point toward the culture medium. When the tissue is cultured in untreated polystyrene dishes, thyroid cells remain in suspension; their aggregates swell progressively and form hollow spheres encompassed by a single layer of cells.

[Demonstration of a basal lamina in cocultures of thyroid cells and embryonal swine skin cells].

Porcine thyroid and embryo skin cells were isolated and cultured. Cultures from each kind of cells, as well as cocultures were fixed twice a week for electron microscopy. On day 8th a basal lamina like material appears only in the cocultures, along the basal plasmalemma of the reassociated thyroid cells.

Ultrastructure and biochemistry of thyroid carcinoma.

Thirty-two thyroid tumors, 9 benign, 23 malignant, and 12 samples of normal thyroid tissue were examined by light and electron microscopy. Thyroglobulin content was also measured in the tissues and, in a limited number of cases, enzymatic activities were determined, such as thyroid peroxidase-iodinase, acid protease, and deiodinase. The presence of significant amounts of 19S, 27S and 12S thyroglobulin was well correlated with the ability of the tumors to accumulate radioiodine.

Microfollicular thyroid carcinoma with amyloid rich stroma, resembling the medullary carcinoma of the thyroid (MCT).

A human thyroid tumor is described which, on light microscopy, exhibited the features of medullary carcinoma of the thyroid (MCT). The cells were arranged in solid lobules or trabeculae, and the stroma was abundant and gave positive reaction for amyloid as assessed by congo red, crystal violet and thioflavin T stains. However, there was microfollicular differentiation in certain portions of the tumor even where the tumor was invasively growing.

Electron microscopy of clear cell thyroid carcinoma.

Three thyroid carcinomas composed in part or entirely of clear cells were studied by light and electron microscopy, and thyroglobulin content was determined by biochemical methods. Clear cells have been found in follicular and papillary thyroid carcinomas and in undifferentiated carcinomas. The clear (wasserhelle) appearance of the cytoplasm was due to the accumulation of glycogen.