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Biomedical subjects

S Savin

Publications and source records attributed to S Savin.

At least 19 recordsLinked to original sources
PubMed1992

Altered terminal glycosylation of thyroglobulin in papillary thyroid carcinoma.

Samples of thyroglobulin (Tg) were isolated from specimens of differentiated thyroid carcinoma of the papillary type and from normal adjacent glandular tissue, and the content of sialic acid was estimated. Also the in vitro incorporation of 14C-sialic acid, in the form of both CMP (cytidine 5'-monophospho-)--activated and non-activated N-acetyl-neuraminic acid, into Tg of malignant and morphologically normal thyroid. The sialic acid content of Tg preparations from papillary thyroid carcinomas varied considerably (0.27-0.92 mg/100 mg Tg). In six cancerous Tg samples the content of sialic acid was markedly lower than that in Tg from the corresponding apparently normal thyroid tissue (0.71:1.11 mg per 100 mg Tg). In addition, in comparison with the control, the incorporation of non-activated 14C-sialic acid into Tg of malignant thyroid tissue was considerably lower (-41%). However, the incorporation of CMP-activated 14C-sialic acid into cancerous Tg was greater than into Tg of morphologically unchanged tissue of the same gland (+29%). The reduced content and incorporation rate of sialic acid into Tg of differentiated thyroid carcinoma is probably the consequence of disturbances in terminal glycosylation of the Tg molecule in malignantly transformed thyroid tissue. The enhanced incorporation of CMP-sialic acid into cancerous Tg suggests that Tg sialylation in carcinoma is probably altered in the sialic acid activation phase.

Carcinoma, Papillary↗
PubMed1992

[Effects of amiodarone on the thyroid gland in euthyroid and hypothyroid animals].

Amiodarone is a benzofurane derivative which contains an appreciable amount of iodine (37%). It is used in cardiology as an antianginal and antiarrhythmic drug. Using guinea-pigs and rats as the animal model systems, the effects of amiodarone on normal and hyperplastic thyroid glands were investigated in eu- and hypothyroid animals. After the amiodarone treatment, considerable differences were observed in the levels of thyroid hormones and in the structure of the gland which proved dependent not only on the length of treatment, but also on animal species and the functional status of the gland before treatment. At extended amiodarone application, the rats with hyperplastic thyroid developed microlesions in epithelium of some follicles.

Amiodarone↗
PubMed1990

Occurrence of antithyroxine antibodies in rabbits immunized with iodine-poor human thyroglobulin.

Thyroglobulin (Tg) is a large glycoprotein with polymorphic structure and its heterogeneity has been demonstrated by many investigators. In order to obtain appropriate antibodies against human Tg which appear in the circulation of patients with thyroid carcinoma, a number of rabbits (19) were immunized with poorly iodinated h-Tg (0.05%). During the period of immunization the level of T3 and T4 was followed in sera, as well as the titre of anti-h-Tg antibodies. The production of antibodies against h-Tg was observed in all immunized rabbits (8, 13, 16, and 54 weeks from the first immunization). Titres of anti-h-Tg antibodies in sera at the 16 and 54-week bleeding were very high (Ka = 2.0 X 10(10) M-1). A few immunized rabbits were found to have a very low concentration of serum T4 (determined by RIA-PEG method). Sera from these animals contained antibodies against T4, but not against T3. Their identification and characterization was performed by a radioimmunological method. In summary, our results show that after immunization of rabbits with low-iodinated, i.e. hormone-poor human Tg, antibodies against thyroxine can be produced. However, occurrence of anti-thyroxine antibodies in some immunized rabbits indicates that the immunogenicity of hormone residues in poorly iodinated h-Tg is much lower than in normal iodinated molecule.

Animals↗
PubMed1989

Enhanced acid protease activity of lysosomes from papillary thyroid carcinoma.

In vitro lysosomal acid protease activity was studied in human papillary thyroid carcinoma (n = 13). As a control, morphologically normal thyroid tissue from the same patient was used in each individual case of carcinoma. Although a marked variation may be observed between individual cases, each examined papillary thyroid carcinoma showed significantly greater activity of acid proteases, both per unit weight of wet thyroid tissue and per unit of lysosomal proteins, in comparison to the corresponding control (range, 24%-248%). In conclusion, it is suggested that enhanced proteolytic activity of lysosomal acid proteases in papillary carcinoma is probably a result of disturbance in catabolic degradation of the thyroglobulin molecule in malignantly transformed thyroid tissue.

Carcinoma, Papillary↗
PubMed1988

Reduced acid protease activity in vitro of lysosomes from thyroid gland of rats chronically treated with propylthiouracil and perchlorate.

We have recently demonstrated that proteolytic activity of lysosomal acid proteases from papillary carcinoma is significantly higher than in morphologically normal thyroid tissue. In the present study the activity of lysosomal acid proteases from parenchymatous proliferated thyroid epithelium, induced by action of antithyroid substances, has been examined in an in vitro system using 125I-labelled rat thyroglobulin as a substrate. Thyroid lysosomes were isolated from rats treated chronically for 3-4 weeks with propylthiouracil (PTU, 0.1% in drinking water) and perchlorate (NaClO4, 200 mg/rat/day) by centrifugation between 800 and 20,000 x g. It was observed that, in contrast to human malignant thyroid tissue, the proteolytic activity of lysosomal acid proteases from antithyroid substance-induced hyperplastic goitre was markedly reduced in comparison with control thyroid tissue (29-50%). Since reduced activity of total lysosomal proteases was found both per unit of wet weight thyroid tissue and per unit of lysosomal proteins, the results suggest that changes in lysosomal enzymes may probably have more quantitative than qualitative nature.

Animals↗
PubMed1987

Reduced proteolytic activity in vitro of lysosomes isolated from "cold" thyroid nodule.

The proteolytic activity of lysosomes isolated from solitary "cold" thyroid nodule and morphologically normal perinodular thyroid tissue was examined in parallel in an in vitro system using 125I-labelled rat Tg as substrate. Lysosomes were isolated by centrifugation of the tissue homogenates between 800 and 20,000 x g. The optimal proteolytic activity of acid proteases from human thyroid tissue was observed between pH 3.6 and 4.8. The evident differences in the proteolytic activity of lysosomal acid proteases between nodular and perinodular tissues were observed. It was found that the activity of lysosomal proteases from "cold" nodule in both the same amount of wet weight thyroid tissue and the same amount of lysosomal proteins was significantly lower (29-54%) than in the morphologically normal perinodular tissue used as a control. The reduced proteolytic activity of lysosomes from patients with "cold" nodule provides further confirmation on the low metabolic activity of thyrocytes in non-functioning thyroid nodules.

Humans↗
PubMed1986

Some characteristics of soluble thyroid proteins in human fetus during morphogenesis of follicular structure.

Soluble thyroid proteins of the human fetus were studied in parallel with the formation of the follicular structure of the gland using polyacrylamide disc electrophoresis and a radioimmunological method for measuring thyroglobulin (Tg). The study covered 24 fetuses obtained after sectio parvae performed at 12-28 weeks of gestation for socio-medical reasons. Before the first trimester of gestation the human fetal thyroid, which did not have an organized follicular structure contained a significant amount of the 12S protein fraction, but only trace amounts of Tg. In the cells of a gland of afollicular structure immunofluorescent material was confirmed by reaction with anti-Tg antibodies. Later, with the formation of follicles and the appearance of follicular colloid, the absolute and relative amounts of Tg in the fetal gland increased, while the 12S subunit decreased. The Tg content in the fetal thyroid was positively correlated with the total weight of the gland, i.e. gestational age. The T4 and T3 contents in Tg of human fetal thyroids (20-24 weeks) amounted to 0.54 +/- 0.39 and 0.12 +/- 0.09 mole/Tg mole, respectively. The 27 S iodoprotein was not found in any of the extracts of fetal thyroids with formed follicles and considerable amounts of follicular colloid. The finding of the 12 S protein in the human thyroid during early fetal life, i.e. in the prefollicular phase, implies a low rate of aggregation of Tg subunits (12 S). The absence of the 27 S iodoprotein from the fetal thyroid with organized follicular structure suggests the yet incomplete morphological and biochemical maturation of the fetal gland.

Electrophoresis, Polyacrylamide Gel↗
PubMed1977

Hemorrhoidectomy--how I do it: results of 444 cryorectal surgical operations.

Based on a three-year personal experience with a large number of patients, cryorectal surgery is a reliable and valuable alternative to excision for the removal of all types of hemorrhoids and most other concomitant pathologic conditions found in 44% of these patients. Excellent results should be anticipated, and complications are minimal. No contraindication has yet been detected.

Cryosurgery↗