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At least 811 records · Page 45Linked to original sources
PubMed1987

[Metastases of the thyroid gland--morphology and clinical aspects of 25 secondary thyroid neoplasms].

Morphological and clinical findings in 25 secondary tumours of the thyroid are described. The most common sources of such lesions were the kidneys (32%), lung (28%) and breast (20%). In the majority of cases, thyroidectomy was performed prior to identification and treatment of the primary cancer. Conversely, among renal cell carcinomas, the metastatic lesion frequently appeared many years after resection of the primary tumour. This suggests that secondary thyroid tumours occasionally may be the only important malignant disease remaining. Hence, adequate surgical treatment may prove to be life-prolonging or life-saving.

Aged↗
PubMed1984

Difference between the thyroid gland of normal and hypomyelinated jimpy mice--a light microscopic study.

A light microscopic quantitative analysis was performed on normal and jimpy male mice for studying the difference between the structures of the thyroid glands of the two animals. The results of this analysis showed that the thyroid gland of the normal mice consisted of numerous homogenous round follicles with cuboidal follicular cells, separated by thin interlobular and interfollicular connective tissue and a few adipose tissue. The thyroid gland of jimpy mice consisted of a few, small follicles surrounded by columnar follicular cells and intraepithelial capillaries, separated by thick connective tissue and abundant adipose tissue. The number of thyroid follicles are significantly less in the jimpy mice than in the normal mice. Another striking difference is that almost every follicular cell surrounding the follicular lumen of jimpy mice is accompanied by an intraepithelial capillary. In addition, the ratio of the number of intraepithelial capillaries to the number of the thyroid follicular cells are significantly higher in the jimpy mice than in the normal mice. The S-follicles or ultimobranchial cysts of the thyroid gland are well developed in the jimpy mice. The parafollicular cells are normal in appearance. Morphological evidence suggested that the thyroid follicular cells of the jimpy mice are very active in the transport, synthesis and release of thyroglobulin, and secretion of thyroid hormones. But owing to the significantly decreased number of thyroid follicles, the inadequate secretion of the thyroid hormones result in the hypothyroidism and the hypomyelination of the jimpy mice.

Animals↗
PubMedDate not supplied

[The peculiarities of separate and combined exposure to low dose-rate gamma-radiation and 232Th nitrate on thyroid gland].

We studied the effects of both: of the separate and of the combined exposure to gamma-radiation (absorbed doses for 30 days were 1.4-1.8 cGy, for 90 days were 4.3-5.4 cGy) and 232Th nitrate (in concentrations 6.0; 20.0 and 60.0 mg/l) on the CBA line mice thyroid gland. Hat is shown the thyroid gland response to the combined exposure is significant in an appearance of non-linear effects of interaction. The intensiveness of the radiation influence (time and doses) is revealed to affect on the biological response direction in thyroid gland. The intensity of this effect was depended on the correlation between the radiation activity and the chemical components concentration. The dispersive analyses showed that all the studied factors caused structural changes in thyroid gland in this experiment, but the gamma-radiation influence causes the primary contribution.

Animals↗
PubMed2000

Expression of nk2.1a during early development of the thyroid gland in zebrafish.

We show here that a zebrafish orthologue of the Thyroid Transcription Factor-1 (TTF-1), nk2.1a, is expressed in the developing thyroid gland. Using a fate mapping approach we found that an early nk2.1a expression domain in the endoderm adjacent to the heart follows morphogenetic movements of the lower jaw, ending up in the region in which the mature thyroid gland is located. We therefore suggest that nk2.1a labels the thyroid precursor cells from somitogenesis stages onwards.

Animals↗
PubMed1980

Ectopic thyroid gland in the submandibular region.

A rare case of an ectopic thyroid gland appearing as a submandibular mass in a 30-year-old female patient is presented. Special emphasis is placed on the origin, unusual location, functioning status, pathology and diagnostic problems created by this interesting case.

Adult↗
PubMed2003

US-guided core-needle biopsy of the thyroid gland.

PURPOSE: To evaluate safety, yield, and accuracy of ultrasonography (US)-guided core-needle biopsy of the thyroid gland. MATERIALS AND METHODS: Findings at 209 consecutive core-needle biopsies of lesions of the thyroid gland in 198 patients (median age, 48 years; age range, 14-80 years) were retrospectively reviewed. In 138 (66%), findings at previous fine-needle aspiration cytologic (FNAC) analysis were nondiagnostic on one to five occasions. Biopsy was performed as an outpatient procedure with direct US guidance by using nonadvancing 16-18-gauge core needles. Hospital records were reviewed 6 months to 5 years following biopsy to determine final diagnosis, delayed complications, and influence of biopsy findings on subsequent patient treatment. Final diagnoses were determined on the basis of findings at excisional histologic analysis, clinical course, or other laboratory values. The sensitivity, specificity, and accuracy of US-guided core-needle biopsy were calculated. RESULTS: One hundred ninety-nine (95%) specimens were adequate for histologic diagnosis. The sensitivity, specificity, and accuracy of core biopsy in differentiating neoplastic (malignant and benign) from nonneoplastic lesions of the thyroid gland were 96% (74 of 77), 89% (109 of 122), and 92% (183 of 199), respectively. The sensitivity, specificity, and accuracy of core-needle biopsy in the detection of malignant neoplasms were 61% (11 of 18), 100% (181 of 181), and 96% (192 of 199), respectively. After US-guided core-needle biopsy, 115 (58%) of 198 patients were treated conservatively, and no evidence of missed tumor manifested during the follow-up period. In the 83 patients who underwent surgical resection, biopsy was performed for therapeutic reasons in 76 (92%) and for diagnostic reasons in seven (8%). There were three cases of small postbiopsy hematomas and one of minor hemoptysis, but none required hospital admission. There were no major complications. CONCLUSION: US-guided core-needle biopsy of the thyroid gland is a safe outpatient procedure with a high diagnostic yield and accuracy, and frequently it obviates surgery in patients in whom findings at FNAC analysis are recurrently nondiagnostic.

Adolescent↗
PubMed1989

Evaluation and characterization of the hyt/hyt hypothyroid mouse. II. Abnormalities of TSH and the thyroid gland.

The hyt/hyt mouse (BALB/cBY-hyt, C.hytRF) provides a useful model for exploring the effect of inherited severe primary hypothyroidism. Studies were undertaken to try to define the basis of the primary hypothyroidism in mice homozygous for the autosomal recessive gene, hyt. These mice had congenital hypothyroidism of fetal onset after 15 days post conception. Through their lifetime, the hyt/hyt mice had reduced serum thyroxine (T4), triiodothyronine (T3), reduced thyroid gland intralumenal colloid on electron microscopy and a 100-fold elevation of TSH-like activity compared to hyt/+ littermates. Thyroglobulin made in hyt/hyt animals was similar in size to normal thyroglobulin which was inconsistent with a major structural thyroglobulin gene defect. The thyroglobulin was iodinated. Marked, erratic dilation of rough endoplasmic reticulum (RER) was noted in hyt/hyt mouse follicular cells. Despite these ultrastructural findings, pulse chase and immunoprecipitation studies with isolated hyt/hyt and normal thyroid glands indicated that normal thyroglobulin processing occurred in the RER and Golgi of the hyt/hyt mice. The hyt/hyt thyroid glands were hypoplastic compared to hyt/+ littermates. Histologically, the hyt/hyt thyroid glands demonstrated an increase in smaller follicular cells, and greater variability in follicular size compared to hyt/+ littermates. Histological and ultrastructural abnormalities in the gland were similar to those seen in certain cases of human congenital hypothyroidism with TSH receptor insensitivity of the thyroid gland. These findings along with the significant TSH elevation, the reduction in colloid and in serum T3 and T4, the efficacy of the hypothalamo-pituitary-thyroid feedback system, and previous observations of reduced iodine uptake and intrathyroidal T4, suggested that primary hypothyroidism in the hyt/hyt mouse might be due to a defect in TSH responsivity of the thyroid gland.

Animals↗
PubMed1981

Dose calculations for 123I, 124I, 125I and 131I in the thyroid gland of the mouse, rat and man and comparison with thyroid function for mice and rats.

To assess the radiotoxicity of various iodine isotopes to the thyroid gland, refined dosimetric calculations of the average dose rate distribution and total absorbed dose were performed using Monte Carlo Procedures applied on a microscopic scale to the electrons emitted by the isotopes and on a macroscopic scale to the photons. The calculated dose rates depended strongly on the average follicle radius, surrounding cell layer thickness and thyroid mass and the total absorbed doses were calculated from them for the mouse, rat and man as a function of the age at the time of administration. The thyroid function of mice and rats after injection of various isotopes, as measured by several authors, was compared with the calculated average absorbed doses in the thyroid and in different parts of the cell layers. Changes in cell layer thickness due to diet were taken into account. The calculated average absorbed dose in the outermost half of the cell layer was found to be better as a prediction of thyroid damage for all species mentioned. The improvement in prediction was obvious for mice and rats, but less important for adult man.

Animals↗
PubMed1989

[In which sonographic thyroid gland findings is scintigraphy unnecessary?].

The indication for the scintigraphy of the thyroid gland can essentially be restricted by the primary application of sonography. Indications for the scintigraphy of the thyroid gland are: Suspicion to malignity and autonomy as well as the clarification of restrosternal strumata and euthyroid strumata with multiple nodes.

Diagnosis, Differential↗
PubMed2003

The role of oxidative stress in physiological and pathological processes in the thyroid gland; possible involvement in pineal-thyroid interactions.

Reactive oxygen species (ROS) play an important role in physiological processes, but - when being in excess - ROS cause oxidative damage to molecules. Under physiological conditions, the production and detoxification of ROS are more-or-less balanced. Also in the thyroid, ROS and free radicals participate in physiological and pathological processes in the gland. For example, hydrogen peroxide (H2O2) is crucial for thyroid hormone biosynthesis, acting at different steps of the process. Additionally, H2O2 is believed to participate in the Wolff-Chaikoff's effect, undergoing in conditions of iodide excess in the thyroid. Much evidence has been accumulated indicating that oxidative stress is involved in pathomechanism of thyroid disease, e.g., Graves' disease, goiter formation or thyroid cancer. Melatonin (N-acetyl-5-methoxytryptamine) - the main secretory product of the pineal gland - is a well-known antioxidant and free radical scavenger, widely distributed in the organism. Mutual relationships between the pineal gland and the thyroid have - for a long time - been a subject of intensive research. The abundant to-date's evidence relates mostly to the inhibitory action of melatonin on the thyroid growth and function and - to a lesser extent - to the stimulatory effects of thyroid hormones on the pineal gland. It is highly probable that under physiological conditions melatonin and, possibly, other antioxidants regulate ROS generation for thyroid hormone synthesis. We believe that melatonin may protect against extensive oxidative damage in the course of certain thyroid disorders or in case of a harmful action of some external factors on the thyroid. Thus, oxidative damage and the protective action of antioxidants, melatonin included, may occur during both physiological and pathological processes in the thyroid, however, this assumption, requires further studies.

Animals↗
PubMed2002

Rat thyroid gland expresses the long form of leptin receptors, and leptin stimulates the function of the gland in euthyroid non-fasted animals.

Leptin is an adipose tissue-secreted hormone, which decreases caloric intake and increases energy expenditure. Some effects of leptin on energy balance seem to be mediated by the hypothalamo-pituitary-thyroid axis. The present study was designed to ascertain whether i) rat thyroid gland expresses the long form of leptin receptor (ObRb) and ii) the prolonged leptin administration (daily subcutaneous injections of 24 nmol/kg leptin for 6 consecutive days) affects thyroid-gland function in this species. Coupled RT-PCR, Western blotting and immunocytochemical findings demonstrated the expression of Ob-Rb as mRNA and protein in the thyroid gland of normal rats. Prolonged leptin treatment raised thyroid-gland weight, and morphometry showed that in the enlarged glands the volume of the follicle epithelium was increased, while that of colloid remained unchanged, so that epithelium/colloid ratio was markedly lowered. In leptin-administered rats, the plasma concentration of TSH was decreased, while those of thyroid hormones (free T3 and total T4) were notably raised. Collectively, these findings suggest that systemically administered leptin stimulates growth and secretion of thyroid gland in the rat, through a direct mechanism involving Ob-Rb.

Animals↗
PubMed1988

Dual mechanisms of regulation of type I iodothyronine 5'-deiodinase in the rat kidney, liver, and thyroid gland. Implications for the treatment of hyperthyroidism with radiographic contrast agents.

Alterations in thyroid hormone status and the administration of radiographic contrast agents can markedly influence iodothyronine metabolism and, in particular, the activity of type I 5'-deiodinase (5'DI). In the present studies, the mechanisms responsible for these effects have been reassessed. As previously reported, the addition of iopanoic acid (IOP) to broken cell preparations resulted in a competitive pattern of 5'DI inhibition. However, the in vivo administration to rats of IOP or 3,3',5'-triiodothyronine (rT3) resulted in a noncompetitive pattern of inhibition of 5'DI in the liver, kidney, and thyroid gland, whereby marked decreases in maximal enzyme velocity (V max) were noted, with no change in the value of the Michaelis-Menten constant. In rats rendered hyperthyroid by the injection of 3,5,3'-triiodothyronine (T3), 5'DI activity was significantly increased in the liver and the kidney. The administration of IOP to these thyrotoxic animals resulted in a rapid loss of enzyme activity characterized by an approximate 80% decrease in 5'DI V max values in both tissues. Furthermore, this inhibitory effect persisted for longer than 60 h after a single IOP injection. IOP administration also decreased 5'DI V max levels in the thyroid gland by 52%. In other experiments, treatment of intact Reuber FAO hepatoma cells with IOP or rT3 induced a rapid decrease in 5'DI V max levels. In cells treated with cycloheximide, these agents enhanced the rate of disappearance of enzyme activity by greater than 12-fold, indicating a predominant effect on accelerating the rate of enzyme inactivation and/or degradation. These studies demonstrate that iodothyronines and other iodinated compounds have complex regulatory effects on 5'DI that entail alterations in the rates of both enzyme activation and inactivation. The previously accepted concept that rT3 and IOP impair thyroxine (T4) to T3 conversion in vivo by acting as competitive inhibitors is an oversimplification. Rather, the clinically beneficial effects of administering these agents to patients with hyperthyroidism may result primarily from the rapid and prolonged inactivation of 5'DI which occurs in the thyroid gland and peripheral tissues.

Animals↗
PubMed2001

[Effect of cultivation conditions on the functional activity of thyrocytes in the organ culture of the thyroid gland in newborn piglets].

In new-born piglets' thyroid gland culture, thyrocytes were capable of synthesising thyroxine and triiodothyronine for over 12 days. A 48-hour decline of the medium pH to 6.45 did not affect further functional activity of the cells. Decrease in temperature to 26-28 degrees C augmented the thyroid hormones level as opposed to continuous cultivation at 37 degrees C. Degradation of the thyroid gland follicular structure induced a change in the hormones biosynthesis. The thyrocytes not arranged in the follicles mainly produced triiodothyronine in concentrations 5 to 8-fold higher than the T4 contents.

Animals↗
PubMed1988

Autoradiographical evidence for increased thyrotropin binding to autonomously functioning thyroid gland tissue.

The aim of this study was to quantify thyrotropin (TSH) binding to individual cells from autonomously functioning thyroid gland tissue (AFTT) in comparison with the corresponding non-autonomous cells. Cryostatic tissue sections from ten thyroid glands with autonomously functioning adenomas were incubated in 125I-labeled TSH. TSH-binding density (TBD) was visualized by means of autoradiography and quantified by means of reflection photometry. Eight out of ten specimens showed a significant (p less than 0.001), up to tenfold increase in TBD of AFTT cells. All ten specimens had a significantly increased number of TSH molecules bound per thyrocyte in comparison both with the corresponding non-autonomous cells and also with tissues from non-functioning thyroid neoplasms (n = 6). The increased TBD of AFTT persisted after transplantation onto nude mice. The paranodular tissue from thyroid glands with scintigraphically compensated adenomas showed in four out of six cases an increased TBD when compared with normal thyroid tissue. It can be concluded that AFTT possesses distinct cytoplasm membrane characteristics as evinced by TSH binding analysis. Increased TSH binding should be considered as a possible cause of metabolic hyperactivity of AFTT cells. The concomitant existence of functional autonomy in the paranodular tissue might lead to a false supposition of a compensated autonomous adenoma as revealed by scintigraphical evidence.

Adenoma↗
PubMedDate not supplied

Experimental studies concerning the mechanism of the thyroid-pineal interrelationship. I. The action of the pineal peptides on the thyroid gland.

Subcutaneous administration of a pineal polypeptide extract, "Crinofizin", to adult male Wistar rats having the thyroid function inhibited by prolonged administration of MTU, has important effects on both the whole organism (slightly correcting the weight increase rate, loweri g cholesterolemia) and the thyroid gland (reducing thyroid hyperplasia and playing a part in various stages of thyroid hormones metabolism). Thus under pineal treatment one can observe a clear tendency to return to the normal values of the thyroid parameters strongly modified by MTU, as RIC, intrathyroid proteic iodine, tissue thyroid hormones distribution, blood PBI and total T4. It appears that these effects of pineal peptides are induced directly on the thyroid and/or via the hypophyso-thyroid axis which they intercept and equilibrate (moderate).

Animals↗
PubMed1976

Fresh and cultured thyroid gland: survival and function after implantation.

Isogeneic or allogeneic thyroid glands were implanted into thyroidectomized recipeint rats. These grafts, either fresh or cultured, were placed in hamstring muscle pocket or under the renal capsule. Survival and function of the grafts were evaluated by: restoration of normal levels of serum thyroxine, weight gain, kidney transamidinase (a thyroxine-induced enzyme), and histological appearance of re-excised implants. A isografts, fresh and cultured, functioned well as ectopic thyroid glands, though restoration of normal serum thyroxine levels was more rapid for the fresh implants. Fresh allografts functioned transiently but then failed due to rejection. No function was detected for cultured allografts, and rejection was seen histologically. The rat thyroid allograft therefore differs from the rat parathyroid allograft, which often can function for several months despite histological evidence of rejection. Maintenance in tissue culture prior to implantation does not appear to alter the longterm immunogenicity of either organ.

Amidinotransferases↗
PubMed1988

[The importance of atypical adenoma of the thyroid gland].

Histological appraisals were made of 8,741 specimens of removed thyroid glands at the Pathologico-Bacteriological Institute of Kaiserin Elisabeth Spital, between 1978 and 1987. Included, according to classification, were 234 atypical adenomas, 47 encapsulated follicular carcinomas, and 158 invasive follicular carcinomas. Atypical adenoma was found to differ histologically from encapsulated follicular carcinoma by non-detectability of vascular invasions. The age distribution of the patients involved failed to provide any conclusive clue to the effect that atypical adenoma was a precursor of encapsulated follicular carcinoma. Females were more often affected than males with atypical adenoma. No recurrence, metastasation nor complaints are recordable at present from any of the surviving patients with atypical adenoma. Patients who died did not reveal any sign indicative of a thyroid disease as cause of death. The five-year survival rate has been 95 per cent for encapsulated follicular carcinoma. Diagnosis of atypical adenoma is not merely a qualitative problem but a quantitative problem as well. Atypical adenoma of the thyroid gland should be classified as a neoplasia in its own right and as absolutely benign.

Adenocarcinoma↗