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At least 631 records · Page 35Linked to original sources
PubMed1984

Presence of adrenocorticotropin-potentiating factors in porcine thyroid glands.

An extract of porcine thyroid gland in 0.1 N acetic acid exerted dose-dependent potentiation of ACTH-induced corticosterone production in isolated rat adrenal cells. The extract by itself manifested no steroidogenic activity. Upon gel-filtration of the extract, potentiating activities were demonstrated in three main peaks with molecular weights of about 10,000, 5,000 and 2,000. These findings indicate the presence of heterogeneous forms of ACTH-potentiating factors in the thyroid. Significant enhancement of ACTH-induced steroidogenesis was readily apparent with three gel-filtration fractions at a lower concentration of ACTH (4.75 pM). At this concentration, dose-dependent potentiation was observed with these three fractions. Enhanced corticosterone production responses by cells preincubated with the thyroid extract were observed and the results indicated the existence of potentiating mechanisms other than inhibition of ACTH proteolysis. The lack of T4, T3 and thyroglobulin in this activity suggests that the activity resides in other constituents of the thyroid.

Adrenal Glands↗
PubMed1997

[Variations in the anatomy and physiology of the thyroid gland in old age].

Recently, the anatomical and physiological modifications of thyroid gland in the elderly have been undergone to many investigations. However, it does not exist an univocal interpretation about the results. Furthermore, non-thyroidal diseases, in the elderly, can modify TSH, FT3 and FT4 serum levels because of an important inhibition of T3 and T4 peripheric conversion; moreover, many drugs have been reported interactions with hypothalamus-hypophysis-thyroid axis in the senescence. At present, the international literature confirm, in the elderly, a reduction of the activity of the hypothalamus-hypophysis-thyroid axis, associated with an adaptation of hormones production; moreover, the thyroid gland undergoes anatomical (weight) and physiological (captation of iodine and hormones synthesis) adaptations, age-related, which witness for a reduction of thyroid function. Furthermore, FT3 and FT4 plasma levels present in old persons are comparable to younger subjects; in fact, in the elderly, it has been proved a reduction of T4 peripheric degradation which equilibrates its low production. So, the progressive reduction of thyroid gland activity in the old men must be explained like an adaptation to the new metabolic rhythm associated with a reduced TSH secretion and with a smaller body mass in the elderly. However, this peculiar new steady-state is not like an hypothyroidism syndrome, because there is not a real hormones reduction.

Aged↗
PubMed1982

Hoarseness associated with lymphoma of the thyroid gland.

Lymphoma of the thyroid gland is usually seen as a rapidly enlarging goiter in older persons, and is associated frequently with dysphagia, hoarseness, and choking. There is infrequent vocal cord paralysis. Three patients with malignant lymphoma seen in a two-year period were hoarse without vocal cord paralysis. Two of them had biopsy-proven lymphoma from within the subglottic trachea.

Aged↗
PubMed1992

Pathophysiology of chemical injury of the thyroid gland.

Many goitrogenic xenobiotics that increase the incidence of thyroid tumors in rodents exert a direct effect on the thyroid gland to disrupt one of several possible steps in the biosynthesis and secretion of thyroid hormones. This includes: (1) inhibition of the iodine trapping mechanism (thiocyanate or perchlorate); (2) blockage of organic binding of iodine and coupling of iodothyronines to form thyroxine (T4) and triiodothyronine (T3) (e.g. sulfonamides, thiourea, methimazole, and aminotriazole, amongst others); (3) inhibition of thyroid hormone secretion by an effect on proteolysis of active hormone from the colloid (lithium or an excess of iodide). Another large group of goitrogenic chemicals disrupts thyroid hormone economy by increasing the peripheral metabolism of thyroid hormones through an induction of hepatic microsomal enzymes. This group includes CNS-acting drugs (phenobarbital, benzodiazepines), calcium channel blockers (nicardipine, nifedipine), steroids (spironolactone), retinoids, chlorinated hydrocarbons (chlordane, DDT, TCDD), polyhalogenated biphenyls (PCB, PBB), and enzyme inducers. Thyroid hormone economy also can be disrupted by xenobiotics that inhibit the 5'-monodeiodinase which converts T4 in peripheral sites (e.g. liver and kidney) to biologically active T3. Inhibition of this enzyme by FD&C Red No. 3, amiodarone, and iopanoic acid lowers circulating T3 levels which results in a compensatory increased secretion of thyroid stimulating hormone (TSH), follicular cell hypertrophy and hyperplasia, and an increased incidence of follicular cell tumors in 2-year or lifetime studies in rats. Physiologic perturbations alone, such as the feeding of an iodine-deficient diet, partial thyroidectomy, natural goitrogens in certain foods, and transplantation of TSH-secreting pituitary tumors in rodents also can disrupt thyroid hormone economy and, if sustained, increase the development of thyroid tumors in rats. A consistent finding with all of these goitrogens, be they either physiologic perturbations or xenobiotics, is the chronic hypersecretion of TSH which places the rodent thyroid gland at greater risk to develop tumors through a secondary mechanism of thyroid oncogenesis.

Animals↗
PubMed1981

[Sources of the cerebrospinal afferent innervation of the pig thyroid gland].

Comparing results of extirpation of the thyroid gland with those obtained at cutting tissues without extirpation of the gland in 1.5--2-month-old pigs of both sex, it was possible to reveal that there are numerous sources of afferent innervation of the thyroid gland in these animals. They include the distal ganglion of the vagus nerve and the cerebrospinal ganglia C1-C6. An essential amount of cells participating in the innervation belong to the distal ganglia of the vagus nerve (main sources), other ganglia concentrate but a small amount of similar neurons (additional sources). A considerable part of neurons participating in the gland innervation are cells of B and C types.

Afferent Pathways↗
PubMed1976

[Congenital disorders of the thyroid gland in experimental litters obtained from mothers subjected to immunization and the action of I-131].

I131 injected to rabbits immunized with homologous thyroid gland on the 19th-20th day of pregnancy led to congenital disturbances of the thyroid gland in the experimental litters in the I and II generations. The functional activity and the activity of proteolytic enzymes of the thyroid gland decreased by the 30th day of the postnatal development. There was revealed a distinct correlation between the content in the thyroid gland of the experimental litters of DIT + MIT and of organic forms--T3 + T4. During the first days after birth DIT + MIT content showed a sharp fall and increased by the 30th day; on the contrary, iodine binding into organic forms decreased with the progress of age. Histological examination of the thyroid glands in the experimental litters demonstrated lymphoid-plasmocytic infiltration, along with connective tissue proliferation, which led to a marked sclerosis and fibrosis of tissues, hypofunction. Beginning from the age of one month there was seen an extensive nodular proliferation, which possibly served as the beginning of parenchymatous goiter formation. The appearance of lymphoid-plasmocytic infiltration in the thyroid gland of the II generation is considered to be the result of congenital predisposition to the autoimmune thyroiditis inlaid in the memory cells and intensified during birth.

Amino Acids↗
PubMed1991

[Diagnosis of cancer of the thyroid gland].

The clinical diagnosis of carcinoma of the thyroid gland (CTG) is a difficult and responsible problem. The importance of cytologic and histologic methods of examination has grown, they determine the therapeutic tactics and the volume of the operative intervention. Clinical examination and operations were carried out on 484 patients with various diseases of the thyroid. The examination included inspection of the thyroid gland, radioisotope scanning, radiological examination of the neck, mediastinum and lungs, ultrasonic study, and aspiration biopsy with further cytologic study of the material. Among the patients treated by surgery 58 (11.9%), 39 females and 19 males (2:1), were found to have CTG. Intraoperative emergency cytologic and histologic study was conducted in 30 patients. Differentiated CTG was revealed in all cases. Among the patients who were operated on 5 died from CTG in a 10-year follow-up period. The importance of aspiration biopsy, under conditions of an outpatient clinic in particular, is emphasized. The results of operative treatment of differentiated CTG show that early diagnosis and appropriate surgical intervention are conducive to a favourable prognosis in relation to the patients survival period.

Adenocarcinoma↗
PubMed2006

Analysis of origin and growth of the thyroid gland in zebrafish.

The zebrafish thyroid gland shows a unique pattern of growth as a differentiated endocrine gland. Here, we analyze the onset of differentiation, the contribution of lineages, and the mode of growth of this gland. The expression of genes involved in hormone production and the establishment of epithelial polarity show that differentiation into a first thyroid follicle takes place early during embryonic development. Thyroid follicular tissue then grows along the pharyngeal midline, initially independently of thyroid stimulating hormone. Lineage analysis reveals that thyroid follicle cells are exclusively recruited from the pharyngeal endoderm. The ultimobranchial bodies that merge with the thyroid in mammals form separate glands in zebrafish as visualized by calcitonin precursor gene expression. Mosaic analysis suggests that the first thyroid follicle differentiating at 55 hours postfertilization corresponds later to the most anterior follicle and that new follicles are added caudally.

Animals↗
PubMed1990

[Ultrasonography of the thyroid gland].

Ultrasonography takes an important place in the diagnostics of thyroid gland diseases. It is a contemporary, uninvasive method of examination, very comfortable for the patient. By applying this examination method it is possible to attain useful data which are related to morphological changes in the gland, while in regard to the functional condition of this organ, it does not present any information. The paper presents ultrasonographic features of individual thyroid gland pathological conditions. The use of puncture under the control of ultrasound can considerably improve the aspiration cito-diagnostics of the thyroid gland.

Humans↗
PubMedDate not supplied

Histiocytosis X of the thyroid gland.

Histiocytosis X rarely involves the thyroid gland and occurs as one of the unusual manifestations of systemic diseases. Diagnosis is based on the identification of the Langerhans' cells in an appropriate background. We report a case of histiocytosis X confined to the thyroid gland that represents the primary manifestation of the disease. A careful histological, immunohistochemical and ultrastructural study has been performed and problems of differential diagnosis are discussed.

Female↗
PubMed2002

Fine needle aspiration cytology of thyroid gland and histopathological correlation--revisited.

Fine needle aspiration of the thyroid gland, followed by cytological studies and their correlation with histopathological diagnosis have been undertaken to assess the effectiveness of fine needle aspiration cytology in diagnosing disorders of this gland. The cases in which discrepancies had arisen between these two methods of diagnosis have also been reviewed. Out of the total 100 patients studied, 28 were cases of simple colloid goitre, 17 of adenomatoid goitre, 10 of autoimmune thyroiditis ranging from lymphocytic thyroiditis to Hashimoto's thyroiditis, 28 of follicular neoplasia, 10 of papillary carcinoma, one of medullary carcinoma, 2 of anaplastic carcinoma and 4 of cystic lesions of the thyroid gland. Although, fine needle aspiration cytology of the thyroid gland was diagnostic in 75% of cases, it did not correlate with the histopathological diagnosis in the remaining 25% of cases. Possible reasons behind these discrepancies have been discussed.

Adolescent↗
PubMed1995

Expression of galectin-1 in normal human thyroid gland and in differentiated and poorly differentiated thyroid tumors.

We previously reported that galectin-1 gene expression increases up to 100-fold in oncogene-transformed rat thyroid cells compared with their normal counterparts and that the relative mRNA levels correlate with the degree of malignancy. In the present study we investigated whether galectin-1 is differentially expressed in human thyroid neoplasms, which range from well-differentiated tumors to undifferentiated anaplastic carcinomas. We analyzed 74 human thyroid specimens of neoplastic, hyperproliferative and normal tissues and several tumor cell lines. Galectin-1 mRNA and protein levels were higher in 6 thyroid carcinoma-derived cell lines than in normal thyroid primary cultures and adenoma cells. Galectin-1 mRNA levels increased in 28/40 papillary carcinomas and in 6/7 anaplastic carcinomas compared with normal or hyperplastic thyroid. Conversely, galectin-1 expression was unaffected in follicular carcinomas and benign adenomas. Immunohistochemical analysis of normal thyroid and papillary carcinoma sections revealed a higher content of galectin-1 protein in neoplastic follicular cells than in normal cells.

Base Sequence↗
PubMedDate not supplied

Study of cells in fine needle aspirations of the thyroid gland.

One hundred nine thyroid nodules were studied by fine needle aspiration cytology and were compared with the histologic sections of these lesions. The correlation of diagnoses between the two techniques proved to be comparable, and the results showed a low incidence of false-negative and flase-positive diagnoses. The criteria and merits of the fine needle aspiration cytology technique used in diagnosing thyroid lesions are presented.

Adenocarcinoma↗