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Biomedical subjects

L Stefăneanu

Publications and source records attributed to L Stefăneanu.

27 records · Page 2Linked to original sources
PubMedDate not supplied

Immunohistochemical demonstration of thyroglobulin in thyroid pathology.

Thyroglobulin (Tg) was detected by the immunoperoxidase method in the following thyroid diseases: euthyroid goiter, Graves' disease, Hashimoto's thyroiditis, folliculo-papillary carcinoma, follicular carcinoma, anaplastic carcinoma and medullary carcinoma. Thyroglobulin was present in all benign lesions. The highest immunohistochemical staining reaction was found in Graves' disease. In euthyroid goiter, some colloid-distended macrofollicles did not show any Tg staining. A heterogeneous pattern of Tg staining was displayed especially by thyroid carcinomas. In most cases of papillary and follicular carcinomas Tg was detected in some neoplastic cells and sometimes in the colloid. There were differences in Tg content between different fields of the same tumor. In all anaplastic carcinomas a negative Tg staining was found. Vizualization of Tg in thyroid carcinomas is important for estimating the degree of differentiation and for indicating the thyroidal origin of metastases of adenocarcinomas.

Humans↗
PubMedDate not supplied

The ultrastructure of the thyroid medullary carcinoma.

The ultrastructure and the morphometrical pattern of secretory granules were studied in six cases of thyroid medullary carcinoma. The tumor cells were fusiform or polyhedral with irregular, mostly elongated nuclei. Phagolysosomes containing a crystalloid material, probably degraded lipoprotein complexes, degeneratively changed mitochondria, moderately developed rough endoplasmic reticulum and Golgi complexes were commonly found. Amyloid occurred as small fibrils in intercellular spaces. Marked dystrophic lesions of tumor cells surrounding amyloid fibrils were found. Numerous roundshaped electron-dense secretory granules were noticed in tumor cell cytoplasms. The morphometrical analysis showed that the size of granules oscillated between 60 and 450 nm with mean values ranging from 171.4 +/- 31.8 to 227.7 +/- 28.1 nm. Frequency distribution curves showed at least two peaks varying with the investigated case at different intervals. In two cases two distinct groups of granules were found within the same cells: one group of electron-dense, compact, smaller sized granules and another group of larger, finely granulated, less dense granules. In the other four cases the granule sizes were more homogeneous. These results might indicate that the granule size depends on the maturation degree and functional activity or that there are several kinds of granules specialized in the secretion of various substances.

Amyloid↗
PubMedDate not supplied

Ultrastructural pathology of the thyroid folliculo-papillary and follicular carcinoma.

Twenty cases of thyroid carcinoma (10 follicular and 10 folliculo-papillary) were ultrastructurally studied. In the follicular carcinoma the most striking features were: microfollicular cavities with microvilli from the apical surface of the tumorous cells, intracellular microlumens, swollen mitochondria sometimes containing electrondense bodies and tightly packed filaments. In the solid sheaths light and dark cells were present. Golgi complexes were disposed in small dense cristae. The nuclei were large, round, oval or with a folded appearance. In the folliculo-papillary carcinoma were found nuclei with an irregular shape containing stage I and stage II inclusions, dilated endoplasmic sacks, closely packed, sometimes dystrophic mitochondria, dense bodies or tightly packed parallel filaments and numerous phagolysosomes. The peroxidase activity wa present as black precipitates in the nuclear envelope or around colloid droplets. The acid phosphatase activity was found as unhomogeneous precipitates inside the lysosomes. From this study it could be concluded that the follicular and folliculo-papillary carcinomas have some common ultrastructural features; the ultrastructural and cytoenzymological patterns suggest marked alteration of the synthesis, storage and secretion of thyroid hormones.

Adenocarcinoma↗
PubMedDate not supplied

The anaplastic transformation of differentiated thyroid carcinoma. An ultrastructural study.

The authors studied 60 thyroid carcinomas (29 folliculo-papillary carcinomas, 20 follicular carcinomas and 11 undifferentiated carcinomas), using ultrastructural, morphometrical and immunohistochemical methods. The anaplastic transformation correlates with the following aspects: decrease of intercellular junctions and of microvilli together with alteration of cell organelles. Immunohistochemically, thyroglobulin is present in various amounts in differentiated carcinoma, but it is absent in undifferentiated tumors. A good correlation is found between the pattern of thyroglobulin and the ultrastructural aspects of neoplastic cells. The authors consider that anaplastic tumors originate from differentiated carcinomas. The decrease of junctions, the modifications in the number and shape of microvilli, the alterations of cell organelles and the changes of thyroglobulin pattern are the principal parameters involved in the anaplastic transformation. These criteria can be also used in order to ascertain an early diagnosis in the thyroid carcinoma evolving anaplastic changes.

Adenocarcinoma↗
PubMedDate not supplied

131I thyroid uptake diminution in chronic alcoholism induced in rats (an autohistoradiographic investigation.

The authors studied the 131I thyroid uptake in chronic alcoholism induced in rats (1.5 g alcohol/kg body weight/day) using autohistoradiographic methods. The intensity of 131I uptake was significantly lower in rats which had ingested alcohol: the proportion of follicles with a strong 131I uptake was 5% in alcohol-fed rats as compared to 25% in control rats. The proportion of moderately labeled follicles was decreased too in alcohol-fed rats (34%) as compared to control animals (47%). Concerning the correlation between follicular volume and 131I uptake. It was found that only a reduced percentage (1.8) of follicles with a volume of 50 microm 3 in alcohol-treated rats showed a strong 131I uptake. In the follicles with a volume exceeding 250 microm 3, the uptake was strongly diminished in alcohol-fed animals. In control rats all thyroid follicles showed various percentages of strong 131I uptake. The authors concluded that alcohol might induce a hypothyroidism revealed by 131I uptake diminution.

Alcoholism↗
PubMedDate not supplied

A light and electron microscopical study of pituitary adenomas.

Authors studied ten cases of human pituitary adenomas, using light and electron microscopical techniques. Based on morphological features correlated with endocrine symptomatology, seven adenomas proved to be functional and three were nonfunctional. The seven secretory adenomas were classified as follows : somatotropic adenomas with densely granulated cells (1 case); prolactinomas with sparsely granulated cells (3 cases); and mixed somatotroph cell - prolactin cell adenomas (3 cases). The nonfunctional tumors belonged to the undifferentiated cell adenoma type. The cells of the densely granulated adenoma resembled the normal cell from which they derived. In the sparsely granulated tumors the secretory granules were smaller and more nonspecific than those of the normal pituitary cells. The cells of the undifferentiated adenomas had sparse organelles and often showed oncocytic transformation. The ultrastructural characteristics of the adenomas are discussed in relation with the type of hormonal secretion and proliferative propension.

Adenoma↗
PubMedDate not supplied

Structure-function relationship in euthyroid goiter (an electronmicroscopical study.

The authors studied the structure-function relationship at the ultrastructural level in euthyroid goiter. Following results were found: small and short microvilli at the apical cell surface: irregular, elongated cisternae of rough endoplasmic reticulum and lysosomes of varying size, sometimes associated with globules or colloid droplets in form of phagolysosomes; irregular, swollen mitochondria, sometimes with a central empty area or an electron-dense amorphous core. The authors concluded that the euthyroid goiter is characterized by a slightly impaired hormone synthesis in the rough endoplasmic reticulum, a damaged mechanism of hormone transport within the cell and respiratory disturbances of the thyreocyte.

Adult↗
PubMedDate not supplied

Ultrastructural morphometry of the secretory granules in thyroid medullary carcinoma.

The authors studied the ultrastructural morphometry of secretory granules in four cases of thyroid medullary carcinoma. An inhomogeneous granules population was found with values ranging from 70 to 450 nm and mean values between 171.4 +/- 31.8 and 222.7 +/- 28.1 nm, respectively. Plurimodal frequency distribution curves showed peaks at 80, 90, 130, 160, 200, 240 and 250 nm. Two possibilities explaining the variation in granules size are discussed: the size of granules could depend on the maturation degree and functional activity or, more probably, there are several kinds of granules containing various biogenic substances, such as calcitonin and ACTH. The granules might play a role in the genesis of amyloid fibrils as well, some granules being located around amyloid fibrils.

Carcinoma↗