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[The effect of aminazin on thyroid gland function and lactation in goats].

The authors showed that cholrpromazine diminished the accumulation of radioactive iodine in the thyroid gland of lactating goats, and at the same time increased the milk yield and richness. This can be attributed to the influence of chlorpromazine on the hypothalamic centres, leading to reduction of thyrotropic hormone secretion and an increase of prolactin synthesis. Rhythmic changes in the thyroid gland function are seen during lactation. During milking or kid nursing there occurred an increase in the thyroid gland function and more catecholamines were secreted; the activity of the thyroid gland diminished and there was an increase in prolactin secretion after milking.

Animals↗

The herbicide metolachlor induces liver cytochrome P450s 2B1/2 and 3A1/2, but not thyroxine-uridine dinucleotide phosphate glucuronosyltransferase and associated thyroid gland activity.

Metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide) is widely used internationally as a corn and cotton herbicide. The metolachlor effects noted in rats during testing for U.S. pesticide registration include increased liver weight and hepatocarcinogenicity associated with eosinophilic foci. These properties, plus nongenotoxicity, are also characteristic of the prototypical rat liver tumor promoter, phenobarbital. Phenobarbital induces hepatic cytochrome P450s CYP2B1/2 and CYP3A1/2 and thyroxine (T(4))-UDP-glucuronosyltransferase (T(4)-UGT), which enhances thyroxine clearance and thus indirectly increases thyroid gland activity. Because other chloroacetanilide herbicides are known to similarly affect rat thyroid gland, this study tested the hypothesis that metolachlor would have these additional phenobarbital-like effects on liver, especially that of T(4)-UGT induction with consequential stimulation of thyroid gland. Effects of metolachlor, fed to male Sprague-Dawley rats for 14 days at the carcinogenic dose of 3000 ppm, were compared to those of equimolar phenobarbital. Liver microsomal CYP2B1/2 and CYP3A1/2 were probed by immunoblotting and T(4)-UGT was measured enzymatically. Serum T(4), triiodothyronine (T(3)), and thyroid-stimulating hormone (TSH) and thyroid follicular epithelial cell morphology and proliferation were used to assess thyroid gland activity. Metolachlor induced CYP2B1/2 and CYP3A1/2 proteins, but unlike phenobarbital, did not affect T(4)-UGT activity. In agreement, serum T(4), T(3), or TSH were unaffected by metolachlor. Also, no significant effects of metolachlor on thyroid gland morphology or follicular epithelial cell height or proliferation were observed. These data demonstrate that metolachlor is an inducer of hepatic CYP2B1/2 activity. But unlike the prototypical CYP2B1/2 inducer phenobarbital, metolachlor does not cause an increase in T(4)-glucuronidation and thyroid gland activation.

Acetamides↗

Thyroid gland size and function in patients with cirrhosis of the liver.

Thyroid dysfunction has long been reported in patients with liver disease, but limited information is available on thyroid gland size in cirrhosis. Most studies were carried out on small, selected series of patients, and no study has measured thyroid volume in relation to the etiology of liver disease. Thyroid volume was measured at ultrasound in 118 consecutive patients with cirrhosis of different etiology and 48 healthy subjects matched for age and sex. No subjects had evidence of overt thyroid disease. The mean volume was increased by 17% (from 16.0 [SD 5.2] ml in controls to 18.8 [7.6] in cirrhosis; P less than 0.025), and thyroid enlargement (antero-posterior diameter greater than 20 mm) was present in 38% of cases, in the presence of hormone values indicative of low-T3 syndrome. No significant differences in thyroid gland size were observed in relation to the extent of liver dysfunction or to the etiology of liver disease. The prevalence of thyroid nodules was similar in controls and in patients with cirrhosis. In only 8% of cases were laboratory values indicative of hypothyroidism, with low free triiodothyronine and raised thyroid-stimulating hormone levels; in these patients thyroid volume was decreased on average by 26%. This was mainly the case with patients with primary biliary and alcoholic cirrhosis. The largest mean thyroid volume was observed in patients with HBsAg + ve postnecrotic cirrhosis, whose thyroid volume was increased on average by 37%, and 53% of subjects had thyroid enlargement. This finding raises the question of a possible direct involvement of the thyroid in hepatitis B virus infection.

Female↗

[Morphological changes in the thyroid gland of rats during various phases of the estral cycle].

The functional state of the thyroid gland and the concentration of thyroid hormones in the peripheral blood were studied in 20 mature female albino rats during their estral cycle. Evaluation of the thyroid functional state was made according to data of histological, morphological (the diameter of folliculi, the height of the thyroid epithelium) and histochemical analysis (determination of NAD and NADP-dehydrogenase, succinatedehydrogenase, lactate dehydrogenase, peroxydase, acid and alkaline phosphatase) as well as biochemical determination of iodine bound with protein (IBP) in the blood plasma and investigation of the ratio of the parameters in question under conditions of the sex cycle. The cyclic changes of the morphological state of the thyroid gland attended by the phases of the estral cycle were revealed. The activation of the organ was observed in proestrus and estrus which was evidenced by high levels of activity of the enzymes under study, high concentration of IBP in the blood and increased height of thyreocytes. A decreased function of the thyroid parenchyma was observed at the period of metaestrus-diestrus.

Acid Phosphatase↗

Impact of nitrate intake in drinking water on the thyroid gland activity in male rat.

The purpose of this study was to determine the effects of nitrate on both the activity of the thyroid gland and other biological parameters. After 5-month treatment, nitrate 150 and 500 mg/l induced a significant decrease in the serum level of thyroid hormone T3. For T4, the 500 mg/l dose only reduced its plasma level. On the other hand, nitrate induced a dose-dependent increase in the weight of the thyroid gland. The histological study of the thyroid gland shows vacuolisation and an increase in the size of the follicles accompanied by a flatness of follicular epithelium with nitrate 150 and 500 mg/l. We concluded that the presence of high concentrations of nitrate in drinking water influence the growth, induce morpho-functional modifications of the thyroid gland and might be considered as a goitrigenic factor.

Administration, Oral↗

Hyperthyroidism of Graves' disease: evidence for only unilateral involvement of the thyroid gland in a 31-year-old female patient.

Hyperthyroidism of Graves' disease (Morbus Basedow) is known to involve the thyroid gland in toto, unlike Graves' ophthalmopathy which clinically may either be unilateral or bilateral. We report a 31-year-old Caucasian female patient who presented with unilateral goiter and clinical and laboratory evidence for hyperthyroidism. High-resolution ultrasonography of the thyroid gland revealed a morphology indicative of an autoimmune thyroid disease strictly limited only to the right lobe. 123I-scintiscanning showed a homogenous but several fold increased uptake of the radionuclide in the right lobe of the thyroid gland, whereas the uptake in the left lobe did not differ from the uptake in normal controls. Cytology of the fine needle aspirate of the right lobe revealed a remarkable inflammatory background mainly by presence of lymphocytes, a finding which was not seen in the cytology of the left lobe. Furthermore, both serum antibodies to TSH-receptors and thyroid peroxidase were significantly increased. Consequently, hyperthyroidism of Graves' disease with the involvement of only one lobe of the thyroid gland was diagnosed.

Adult↗

Metastatic carcinoma of the thyroid gland as the initial manifestation of the disease.

During the past 38 years, 260 patients with thyroid carcinoma have been operated upon at the University of California Hospital. In 26 of these patients the first symptom was a mass distant from the thyroid gland, and the gland was considered normal on clinical examination. In all but three of the 26 cases a small carcinoma of the thyroid gland was observed at operation or in pathological examination. Radical neck dissection with either total lobectomy or total thyroidectomy would seem to be the operation of choice in the treatment of these patients. The ultimate prognosis, even in the presence of metastases, is relatively good.Primary carcinoma of the thyroid gland should be considered in the presence of tumors of the side of the neck even in the absence of palpable nodules in the gland itself.

Carcinoma↗

[Teratoma of the thyroid gland in children].

Two cases of teratoma of the thyroid gland occurring in children are presented. Both tumors were discovered shortly after birth and were not associated with clinical hypothyroidism. One of the patients was thoroughly studied from the endocrinological point of view utilizing several techniques. There was some iodine uptake by the gland, formation of tirosine and thyroid hormones as well as their release into the blood serum. The clinical and pathological features of teratoma of the thyroid are discussed.

Age Factors↗

[Reoperations in thyroid gland cancer].

Results of reoperation for the thyroid gland cancer (THGC) were analyzed in 189 patients for 1981-2001 yrs period. Majority of patients were primarily operated in other hospitals of Ukraine. Thorough characteristic of the cancer forms, terms of reoperation performance, results of histological investigation of the tumor are adduced. Large frequency (41.2%) of the operation performance for THGC recurrences in term up to one years after performance of primary intervention trusts the necessity of operative intervention performance on thyroid gland (THG) in specialized centre by experienced surgeons. Absence of malignant growth in the THG stump while performance of definitive thyroidectomy in 60% of observations is not the cause to reject of doing it because the conduction of radioiodine therapy is possible after complete excision of the THG tissue. Examination and ultrasonographic investigation of the THG region and of cervical lymphatic nodes after performance of operation for THGC is recommended to conduct no less than once in 6 months.

Adolescent↗

Management of the thyroid gland with laryngectomy for cT3 glottic carcinomas.

Is routine hemithyroidectomy justified in laryngectomy for laryngeal carcinoma? Hemithyroidectomy with laryngectomy causes hypothyroidism in up to 25% of patients, and if combined with radiotherapy, in up to 70%. In this review of 102 total laryngectomies with routine hemithyroidectomy for cT3 glottic carcinoma, laryngeal carcinoma involved the thyroid gland in two. Both had subglottic tumour extension. The tumour approached within 3 mm of the thyroid capsule in seven. It is proposed that thyroidectomy should be performed only in selected laryngeal carcinomas. Intraoperative assessment of the thyroid gland should determine the need for thyroidectomy in glottic and transglottic carcinomas. Carcinoma invasion of the thyroid gland should be confirmed by frozen section before proceeding to thyroidectomy. In the absence of thyroid gland involvement, both thyroid lobes may be preserved. Total thyroidectomy should be performed if the thyroid gland has been invaded. Total thyroidectomy should be routinely performed with subglottic carcinomas.

Adult↗

Computed tomography of the thyroid gland.

Many imaging modalities are used in the investigation of the thyroid gland. In this multitude of methods, none of the applied modalities per se is able to discriminate between the benign or malignant nature of a thyroid lesion with absolute certitude. In this thesis, CT-imaging in various conditions of the thyroid gland is described. At the same time, the advantages and the risks of the application of free iodine as selective contrast agent for thyroid imaging in selective cases is studied. In chapter II a review of imaging modalities is described. A survey is given of the value of each imaging modality for the daily routine practice. In chapter III, relevant technical aspects of CT scanning with respect to the thyroid investigation are highlighted. These include technical possibilities typical for CT-scanning, dosimetric aspects and the patient preparation protocol. The CT-scan procedure is described for the neck region and the mediastinum. Chapter IV summarizes some important aspects of the iodine metabolism of which the radiologist should be aware. Chapter V describes the advantages of our scanning method in different patient groups. Evidence is obtained that CT-investigation of patients with a MEN 2-syndrome in the early assessment of tumor localization is of value. Application of CT in patients with a scintigraphically demonstrated cold nodule is shown to have consequences. Refinement of this diagnosis is possible and of additional value. The appearance of a multinodular goiter on CT is shown to be characteristic. Typical CT-features of this lesion are described which makes a strong indication in the direction of the histological diagnosis possible. With respect to the mediastinal masses of unknown origin, CT-signs of these lesions are considered. CT-examination can differentiate between goiters, benign cysts, infiltrative lesions and enlarged lymph nodes. Some attention is paid to future technical developments of CT, i.e., dual energy scanning. Early experiences are promising, especially in the field of thyroid imaging.

Adolescent↗

Inappropriate thyroid gland ablation in patients with generalized resistance to thyroid hormone. A common sequela of a rare disorder.

Generalized resistance to thyroid hormone is one of several rare disorders of thyroid metabolism that can be associated with confusing symptoms and signs. Five cases of generalized resistance to thyroid hormone that were misdiagnosed with thyrotoxicosis, leading to unnecessary thyroid gland ablation and iatrogenic hypothyroidism, are reviewed herein. These cases illustrate the point that a careful review of the history, physical examination, and laboratory data, as well as an understanding of hormonal feedback relationships, will greatly benefit the practitioner in evaluating the patients with thyroid dysfunction. Consultation with an endocrinologist may be helpful to establish the correct diagnosis and avoid unnecessary treatments.

Adult↗

Isolated carcinoid tumor metastatic to the thyroid gland: report of a case initially diagnosed by fine needle aspiration cytology.

BACKGROUND: Neuroendocrine tumor metastatic to the thyroid gland is rare and may be difficult to differentiate from primary thyroid neuroendocrine tumors, such as medullary thyroid carcinoma (M/ITC). This report describes an unusual case of bronchial carcinoid metastatic to the thyroid diagnosed by fine needle aspiration cytology (FNAC). CASE: A 42-year-old woman with an undiagnosed bronchial carcinoid tumor presented to our clinic with a solitary nodule in the thyroid gland. FNAC of the nodule showed loosely cohesive groups of cuboidal tumor cells with scant, slightly granular cytoplasm; centrally located nuclei with a coarsely granular, salt-and-pepper chromatin pattern and inconspicuous nucleoli. Immunocytochemically the tumor cells were positive for neuron-specific enolase, chromogranin and synaptophysin and negative for thyroglobulin, calcitonin and carcinoembryonic antigen. The cytologic diagnosis of a metastatic neuroendocrine carcinoma was confirmed histologically. CONCLUSION: Metastasis to the thyroid gland may pose a diagnostic problem, particularly with tumors of neuroendocrine origin, as these have similar cytologic features in various organs. The correct preoperative cytologic diagnosis of metastatic carcinoid tumor in patients without a prior history of cancer and differential diagnosis with MTC are crucial because prognosis, workup and treatment are different in each.

Adult↗

Solitary intracranial metastasis of follicular carcinoma of the thyroid gland clinically mimicking a meningioma.

We describe a rare case of solitary metastasis of follicular carcinoma of the thyroid gland into the petroclival region in a 58-year-old woman. The metastasis was the first and only manifestation of the disease. The histology of the tumor, differential diagnosis and clinical course are discussed. In a few similar cases described so far the tumor was always a well or moderately differentiated follicular carcinoma located in the petroclival region. As in this presentation, these cases also clinically mimic a meningioma. The differential diagnosis includes adenoma of the thyroid gland and thyroid gland dystopia. We demonstrated the primary focus of carcinoma within the thyroid after its detailed examination initiated by our finding. The clinical outcome of such rare cases is usually excellent, much better than in metastases of papillary carcinoma into the brain.

Adenocarcinoma, Follicular↗

Observer variation in ultrasound assessment of the thyroid gland.

In order to determine observer variation in the assessment of the thyroid gland by ultrasonography, two specialists (one endocrinologist and one radiologist) independently evaluated 76 thyroid glands, and assessed the sonogram as homogeneous, inhomogeneous, containing a solitary solid lesion or a solitary cyst in each of 152 thyroid lobes. The observed agreement between the two observers ranged from 0.80 to 0.91. By the use of the kappa coefficient the observed agreement was adjusted for change agreement. Kappa can vary from -1 (total disagreement) to +1 (total agreement) and kappa values between 0.55 and 0.60 were found. Among 152 lobes a solitary solid lesion, i.e. a nodule, was found in 22 lobes by the two observers; however, they only agreed on a classification in 10 lobes (45%). Clinicians should be aware of the moderate agreement between observers in thyroid ultrasonography.

Adult↗

Carcinogenic effect of di-isopropanolnitrosamine on the rat thyroid gland.

Up to a 50% rate of thyroid gland tumours was induced in Sprague-Dawley rats after s.c. administration of di-isopropanolnitrosamine (DIPN). The neoplasms occurred both unilaterally and bilaterally, and were identified histologically as adenomas and adenocarcinomas of follicular epithelium origin. In a few instances, adenomas were observed as early as 18 weeks after commencement of treatment. Most adenocarcinomas could be observed macroscopically, and frequently demonstrated infiltration into the surrounding muscles.

Adenocarcinoma↗

Unusual thyroid gland vascularization.

During a dissection course, an unusual vascularization of the thyroid gland was found in a 69-year-old human male cadaver. On the right side, two arteries from the thyrocervical trunk supplied the lower half of the right lobe of the thyroid gland: the inferior thyroid artery and an additional vessel with a main trunk, found to be split into an upper and lower branch at the level of the longus colli muscle. The upper branch supplied the inferior constrictor pharyngeal muscle and the esophagus, whereas the lower branch coursed, at first, onto the trachea and finally leaving it to anastomose with the inferior thyroid artery.

Aged↗

[The thyroid gland as a modulator of ovarian development and histophysiology].

On the base of the complex of experiments modeling disfunctional states of the thyroid gland were proved the most importance of the thyroid gland hormones in regulation of development and histophysiology of the ovary. There were analyzed possible mechanizmes by with thyroid gland hormones influence on this biological processes and its role in general system of the neurohumoral regulation of sexual function.

Aging↗