Biomedical subjects

Andrea Cerná

Publications and source records attributed to Andrea Cerná.

3 recordsLinked to original sources

PubMed2006

Neoplastic transformation of the thyroid gland is accompanied by changes in cellular sialylation.

Cancer of the thyroid gland is one of the most common endocrine diseases. Histological evaluation is often complicated by difficulty in distinguishing between benign and malignant lesions. Abnormal glycosylation of cell structures, including changes in sialylation, is a feature of the neoplastic transformation process. The aim of this study was to evaluate associations between neoplastic changes in the thyroid gland and changes in sialylation, with reference to its terminal linkage type. Lectin histochemistry using three sialic acid-binding lectins: Tritrichomonas mobilensis lectin (TML), which recognizes sialic acid without linkage preference; Maackia amurensis leukoagglutinin (MAL), which preferentially binds alpha-2,3-linked sialic acid; and Sambucus nigra agglutinin (SNA), which preferentially binds alpha-2,6-linked sialic acid, were used for detection of sialylated glycoconjugates in 50 human thyroid gland specimens. These included papillary, follicular, oncocytic, medullary and anaplastic carcinomas, follicular adenomas and benign follicular and parenchymatous goiter. The luminal surface of follicular cells in normal thyroid glands, adenomas and goiters showed weak or absent labelling for sialic acid. Malignant transformation of the gland was accompanied by an increase of sialic acid positivity on follicular epithelial cells, especially of alpha-2,3-linked sialic acid. Strong luminal positivity for sialic acid was found in papillary carcinomas, whereas moderate positivity was seen in follicular carcinomas. Inconsistent, weak positivity for sialic acid was documented in medullary and anaplastic carcinomas. Increased membrane sialic acid on thyroid gland cells may be an important diagnostic pathological finding, that could be useful in distinction of malignant from benign thyroid lesions, especially with respect to aspiration cytology diagnostics.

Cell Transformation, Neoplastic↗

PubMed2002

Changes in sialic acid expression in the lung during intrauterine development of the human fetus.

Sialic acid is a component of glycoproteins that influences enzymatic and receptor functions of cells. During proliferation and differentiation of tissues, sialic acid can serve as a recognition determinant in intercellular communication and interactions of cells with the extracellular matrix. In the present study, sialic acid expression in relation to developmental maturity of the lung has been studied. We analyzed 12 necroptic lung specimens from foetuses of different gestational ages from the 15th week to the neonate. Sections were stained histochemically using 3 lectins specific for sialic acid: Tritrichomonas mobilensis lectin (TML), specific for sialic acid without linkage preference, Sambucus nigra agglutinin (SNA), specific for alpha2,6-linked sialic acid, and Maackia amurensis leucoagglutinin (MAL), specific for alpha2,3-linked sialic acid. MAL positivity dominated over SNA positivity showing prevalence of alpha2,3-linked sialic acids to be homogeneously distributed in the lung at the canalicular stage of development. In more mature lungs, well-differentiated bronchial epithelium showed strong sialic acid expression of both linkages. Sialic acid with alpha2,6 linkage dominated in vascular endothelium. Our results showed a slight decrease in sialic acid expression in lungs with gestational age to a relative minimum before birth. Lectin staining of mature lung tissue showed intense sialic acid expression in alveolar epithelial type II cells. Changes in expression of specific sialic acids during differentiation of the lungs may be useful as marker of the degree of maturity of the foetus.

Animals↗

PubMed2002

Sialic acid expression in autoimmune thyroiditis.

Autoimmune diseases of the thyroid gland are among the most frequent endocrine disorders. The present study analyzes expression patterns of sialic acids in these diseases. Three lectins specific for sialic acids were used for the histochemical analysis of surgical specimens of the thyroid gland: Tritrichomonas mobilensis lectin that stains all types of sialic acids, Maackia amurensis leukoagglutinin that stains sialic acids with alpha2,3 linkage and Sambucus nigra agglutinin that stains sialic acids with alpha2,6 linkage. In autoimmune thyroiditis, there was a significant increase in sialic acid expression in epithelial cells, especially on luminal membranes of follicular cells. The alpha2,3 linkage dominated over the alpha2,6 linkage. Lymphocytes of patients with Hashimoto thyroiditis, especially in germinal centers, showed strong expression of alpha2,6-linked sialic acids on their cell membrane. Vascular endothelium was positive in all specimens. It can be concluded, that there is a significant increase in sialic acid expression in autoimmune diseases of the thyroid gland, predominantly of sialic acids with alpha2,3 linkage, whereas the sialylation pattern of lymphocytes in Hashimoto thyroiditis was also different.

Animals↗