Structural changes in the angiofollicular units between active and hypofunctioning follicles align with differences in the epithelial expression of newly discovered proteins involved in iodine transport and organification.

In animals, as well as in humans, the thyroid gland is made of active follicles, with cuboidal cells and hypofunctioning follicles, with flattened cells. In this study, the functional status of human follicles was dissected out, based on immunohistochemical detection of TSH receptor, Na(+)/I(-) symporter, pendrin, thyroperoxidase (TPO), thyroid oxidases (ThOXs), and T(4)-containing iodinated Tg (Tg-I). To ascertain that angiofollicular units exist in the human, we studied the microvascular bed of each follicle, in correlation with detection of vascular endothelial growth factor (VEGF), of nitric oxide synthase III, and of endothelin in normal and goitrous thyroids. In hypofunctioning follicles, pendrin, TPO, and ThOXs were not detected, and there was no Tg-I in the colloid. At the opposite, in active follicles, pendrin, TPO, and ThOXs were detected in thyrocytes, and Tg-I was present in the colloid. In normal and goitrous thyroids, the capillary networks surrounding active follicles were larger than those surrounding hypofunctioning follicles. Immunoreactivity for nitric oxide synthase III and endothelin was solely detected in active follicles. Only a few follicles in normal thyroids were immunostained for VEGF, regardless of their functional status. In multinodular goiters, VEGF was detected in contact with the extracellular matrix at the basal pole of the cells. In conclusion, the present study endorses the likelihood of angiofollicular units in the human thyroids. Vascular changes are related to the functional status of thyrocytes.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Structural changes in the angiofollicular units between active and hypofunctioning follicles align with differences in the epithelial expression of newly discovered proteins involved in iodine transport and organification.

In animals, as well as in humans, the thyroid gland is made of active follicles, with cuboidal cells and hypofunctioning follicles, with flattened cells. In this study, the functional status of human follicles was dissected out, based on immunohistochemical detection of TSH receptor, Na(+)/I(-) symporter, pendrin, thyroperoxidase (TPO), thyroid oxidases (ThOXs), and T(4)-containing iodinated Tg (Tg-I). To ascertain that angiofollicular units exist in the human, we studied the microvascular bed of each follicle, in correlation with detection of vascular endothelial growth factor (VEGF), of nitric oxide synthase III, and of endothelin in normal and goitrous thyroids. In hypofunctioning follicles, pendrin, TPO, and ThOXs were not detected, and there was no Tg-I in the colloid. At the opposite, in active follicles, pendrin, TPO, and ThOXs were detected in thyrocytes, and Tg-I was present in the colloid. In normal and goitrous thyroids, the capillary networks surrounding active follicles were larger than those surrounding hypofunctioning follicles. Immunoreactivity for nitric oxide synthase III and endothelin was solely detected in active follicles. Only a few follicles in normal thyroids were immunostained for VEGF, regardless of their functional status. In multinodular goiters, VEGF was detected in contact with the extracellular matrix at the basal pole of the cells. In conclusion, the present study endorses the likelihood of angiofollicular units in the human thyroids. Vascular changes are related to the functional status of thyrocytes

Human thyroglobulin reference material (CRM 457). 2nd Part: Physicochemical characterization and certification.

This report describes the characterization of a purified human thyroglobulin (Tg) reference material, and details the procedures used in its certification. The purified Tg is intended to be used as a primary reference material to establish calibration of working serum based reference material for immunoassay procedures. The programme involved the participation of 15 European laboratories and one laboratory from the United States. The physicochemical characterization showed by polyacrylamide gel electrophoresis and immunoblotting that the purified Tg had for the major part the expected molecular size of 660 kDa with traces of lower molecular forms. The amino acid composition was close to that demonstrated for the cDNA and the content of iodine was in keeping with a moderately to highly iodinated Tg. The mass concentration in reference material RM 457 is certified to be (0.324 +/- 0.018) g/L on the basis of protein determined by the Lowry method and supported by nitrogen determination, absorbance measurement, and amino acid analysis. This reference material is considered the first step towards decreasing the interlaboratory variability between Tg methods of measurement.Journal ArticleSCOPUS: ar.jinfo:eu-repo/semantics/publishe