[Effect of adrenalectomy on the function of the thyroid gland and the metabolism of the thyroid hormones in rats].
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Adrenal Glands↗
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[Lymphography of the thyroid gland. 1].
The authors carried out a lymphographic examination in 11 patients with various diseases of the thyroid gland. Lymphography proved to be an effective and harmless diagnostic method in pathological changes of the thyroid gland. Different structure of the thyroid gland tissue was revealed on the lymphograms depending on the character of the pathological process. In establishment of the diagnosis one should take into consideration the structure of the thyroid gland tissue, the structure of the cervical lymph nodes, and possibilities of their filling with the contrast agent, the amount, the rate and difficulties encountered in the administration of the contrast substance.
Adolescent↗
[Critical review of the relation between endocrine glands, with special reference to the thyroid gland, and aging; notes on an essay of M.G. Good on a general theory of aging].
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Aging↗
Endocrine intervention during irradiation does not prevent damage to the thyroid gland.
Radiation to the head-neck region may damage the thyroid gland, leading to hypothyroidism or thyroid carcinoma. Outcomes of radiation protection by lowering plasma thyroid-stimulating hormone (TSH) have thus far been ambiguous. Our aim was to evaluate the radioprotective effect of inhibiting the thyroid gland's activity during x-radiation. For this purpose, of 80 5-week old Wistar rats, 64 received cervical irradiation with 15 Gy (single dose). During irradiation, endocrine intervention was done, using thyroxine (T(4)), T(4) plus iodine, or iodine alone compared to placebo. During the endocrine interventions and follow-up, TSH and T(4) concentrations were measured periodically. Histologic examination of thyroid, pituitary gland, or the hypothalamus and any suspect lymph nodes, lungs, and liver was performed after 6 and 54 weeks. It was found that during the endocrine intervention, plasma levels of TSH were lower in rats given T(4) and higher in rats given iodine. After 6 and 54 weeks, no significant reduction in hypothyroidism or thyroid carcinoma was found between the different groups of rats given any endocrine intervention or no intervention. In conclusion, the administration of T(4), iodine or the combination during x-irradiation does not protect against radiation-induced thyroid damage.
Animals↗
Cancer of the thyroid gland in infants and children.
Carcinoma of the thyroid gland is unusual in children and represents only about 3% of pediatric malignancies. Surgical management is the principal method of treatment, but there is considerable controversy regarding exactly how much of the thyroid gland should be removed for adequate treatment. There also is controversy regarding the use of fine-needle aspiration (FNA) in the evaluation of potentially neoplastic thyroid lesions. In this report, the pertinent literature is reviewed regarding these issues. Moreover, this report will discuss recent discoveries that have elucidated some of the molecular biological events responsible for the development of thyroid cancer.
Child↗
Light and electron microscopic study of the thyroid gland of the camel (Camelus dromedarius).
The thyroid gland of sexually immature dromedary camels was studied using both light and electron microscopy. The thyroid gland contained follicles of different sizes in both summer and winter. However, most of the follicles were large in summer and small in winter. The large follicles were lined by very low cuboidal or semi-squamous follicular cells whereas the small ones were lined by high cuboidal or low columnar follicular cells. Electron microscopy showed that the very low cuboidal follicular cells were poor in organelles and were considered hypoactive. High cuboidal follicular cells on the other hand, were rich in organelles that included mitochondria, cisternae of rough endoplasmic reticulum, secretory vesicles, colloid droplets, heterosomes and autophagic vacuoles; they were considered to be very active. The possible role played by these organelles is synthesis of thyroglobulin and liberation of tri- and tetraiodothyronine is discussed. A few degenerate follicular cells were infrequently encountered in the camel thyroid. Parafollicular (C) cells were not seen in this study either with light or electron microscopy.
Animals↗
Hashimoto's thyroiditis and carcinoma of the thyroid gland.
Seven cases of Hashimoto's disease (HT) occurring in association with carcinoma of the thyroid gland are presented. The diagnosis of HT was not reached before surgery in any of the cases; it was an incidental histopathological finding. There was no case of pure papillary cancer: two specimens showed mixed papillary and follicular cancers, four revealed follicular carcinomas (one of them with anaplastic areas) and one medullary neoplasm. Other authors, however, have reported that pure papillary carcinoma occurred with significantly greater frequency in thyroids also displaying Hashimoto's disease. Total thyroidectomy was performed in all seven patients and one patient with anaplastic follicular cancer also received external irradiation. TSH suppressive therapy was given postoperatively. All these patients are alive with no evidence of further disease after seven to 17 years of follow-up study, whereas the mortality in our total series of thyroid cancers, even in patients with low-grade malignancy, was about 9%. Thus the prognosis of patients with carcinoma of the thyroid gland with coexisting Hashimoto's disease is better than that of patients with carcinoma of the thyroid gland alone. Hashimoto's thyroiditis does not seem to be a premalignant lesion. There was no evidence suggesting that thyroid carcinoma originated in the proliferating epithelium of Hashimoto's thyroiditis. It would appear that thyroid carcinoma stimulates the development of HT in some patients and that the presence of the autoimmune inflammatory reaction and the circulating antibodies retard growth and dissemination of carcinoma of the thyroid gland.
Adolescent↗
Disorders of thyroid gland in India.
The profile of thyroid disorders encountered in pediatric and adolescent age groups in India is similar to that seen in most parts of the world except for the prevalence of iodine deficiency disorders in certain endemic regions of this country. Clinical presentation is most commonly for hypothyroidism and goiters and infrequently for hyperthyroidism. Of nearly 800 children referred for thyroid problems, 79% had hypothyroidism (goitrous as well as nongoitrous), 19% had euthyroid goiters and 2% had hyperthyroidism. Hypothyroidism was due to thyroid dysgenesis in 75% (aplasia/hypoplasia--50% and ectopic thyroid gland 25%), thyroiditis in nearly 5% and dyshormonogenes is in 20%. The incidence of congenital hypothyroidism in our experience of screening nearly 40,000 newborns is about 1 in 2,640, which is much higher than the worldwide average of 1 in 3,800. Diagnostic delay in hypothyroidism is common and is related to lack of awareness amongst primary healthy care practitioners and family physicians as well as the cost and availability of laboratory investigations. This delay, compounded with inadequate therapeutic surveillance is responsible for the poor outcome in affected children. High incidence of dyshormonogenesis, inherited as autosomal recessive trait also calls for genetic counselling and routine sibling examination. Our results of family studies on first degree relatives of children with thyroiditis revealed presence of antimicrosomal antibodies in 43% and thyroid disease in 26%. Many etiologic factors cause goiters which may be functionally euthyroid or hypothyroid with almost equal frequency in our series. In nearly 200 schools children surveyed for goiter prevalence, 8% in high socioeconomic groups and about 21% in the low income group, had goiters. Female predominance was marked. However, iodine deficiency was not the sole cause as revealed by dietary survey and urinary iodine estimations. Hyperthyroidism is infrequent, less severe and in our experience responded well to long-term administration of antithyroid drugs. A high index of clinical awareness and education of primary health workers will help a great deal in improving the ultimate outcome in children with thyroid disorders/hypothyroidism.
Adolescent↗
Radionuclide imaging of the thyroid gland: patterns, pearls, and pitfalls.
Optimal thyroid scintigraphy requires an understanding of 1) the embryology, anatomy, and physiology of the thyroid gland; and 2) the properties of the 2 common imaging agents, technetium-99m pertechnetate (Tc-99m) and radioiodine (1-123). The normal gland has a characteristic scintigraphic pattern with these tracers and its uptake can be quantified with 1-123. Thyroid diseases often produce characteristic abnormal patterns. These abnormal patterns could be described as diffuse or focal, homogeneous or heterogeneous, increased or decreased. "Extrathyroidal" localization can be seen with esophageal activity, ectopic tissue, thyroglossal duct cyst, and substernal goiter. Thyroid scintigraphy of neonates, as a follow up to abnormal blood screening, demonstrates typical etiologic patterns. The first step in evaluating a patient with suspected thyroid disease is correlating the normal or abnormal scintigraphic pattern with available biochemical data, clinical history, and physical examination. By integrating the interpretive and technical "pearls" and "pitfalls" outlined in this article, the radiologist can be more confident in establishing a proper diagnosis.
Artifacts↗
High incidence of normal thyroid gland volume in patients with Graves' disease.
Thyroid function and thyroid gland volume, ultrasonically determined, were investigated in ninety consecutive untreated patients with Graves' disease. Twenty-eight patients (31%) had no clinically detectable goitre. Median thyroid gland volume was 31 ml (range 12-99 ml). Twenty-one patients (23%) had a normal calculated thyroid volume. Thyroid volume did not correlate with any measure of thyroid function. The lack of a goitre in a large portion of patients with Graves' disease could be responsible for delayed diagnosis and subsequent treatment of these patients.
Female↗
[Demonstration of sensor nervous endings in the rat thyroid gland].
The nerve sensitive endings or receptors of the thyroid gland have been studied in twenty adult male rats. Their morphology, their acetyl-cholinesterase specific activity, their mono-amino-oxidase activity and VIP were investigated. Few but constant nerve sensitive endings were observed in the thyroid gland. These receptors were subdivided by their morphology in the next groups: pear-shaped receptors with capsule; capsuled spherical receptors located near vascular walls; ovoidal receptors with capsule and glomerular structure; simple or complex mace-shaped receptors without capsule. The acetyl-cholinesterase technique could just show a unique type or receptor, which corresponds with last one described. The mono-amino-oxidase technique can not show any type of receptors. VIP was not localized immunohistochemically in the sensitive endings of the thyroid gland.
Animals↗
[How to treat benign thyroid gland nodules].
Investigations within the framework of the thyroid gland initiative "Papillon" turned up an unexpectedly high level of pathogenic findings. Determination of TSH and sonography are considered the pillars of the diagnostic evaluation of the thyroid gland. Useful further investigations aimed at excluding functional disorders are, for example, the determination of FT3 and FT4 or a search for autoantibodies. To investigate suspicious nodules and to exclude malignant processes, additional scintigraphy and, were indicated, fine-needle puncture can be applied. Depending on the individual situation of the patient, the therapeutic option of choice is surgical operation or treatment with iodine-31 therapy. Medical treatment of nodular goiter is currently still controversial.
Biopsy, Fine-Needle↗
[C-cell tumors of the thyroid gland].
Morphological description of 59 C-cell tumours of the thyroid gland is presented. The C-cell tumours are very variable both cytologically and histologically and include monomorphocellular, spindlecellular, and polymorphocellular variants. Grimelius and Sevier-Munger argirophilic reactions are most suitable for histological diagnosis of apudomas of the thyroid gland. The epithelial genesis of C-cell tumours of the thyroid gland is suggested.
APUD Cells↗
Effects of radiation on rabbit thyroid gland ultrastructure.
The ultrastructure of irradiated rabbit thyroid gland (0 Gy, as control, 4 Gy, 8 Gy, 12 Gy, 16 Gy and 20 Gy X-ray) is studied. The thyroid gland of the control group shows ultrastructural features similar to those described in other mammals. Modifications in follicular ultrastructure and interfollicular connective tissue ultrastructure as well as the presence of small thyroid follicles, probably neoformed, are found to be dose-dependent. Follicular epithelium varies from simple cuboidal to simple squamous, the latter being characteristic of the highest X-ray dose. Follicular cells show numerous cytoplasmic light vesicles and a very extensive rough endoplasmic reticulum consisting of vacuolated cisternae. Sloughed cells are present at 8 Gy. A well-developed interstitial glandular tissue consisting of extensive extracellular matrix, abundant collagen fibres and dilated, irregularly outlined capillaries are also present.
Animals↗
[THE LYMPHATICS OF THE THYROID GLAND. EXPERIMENTAL ANATOMICAL STUDY IN RELATION TO THE TREATMENT OF THYROID CANCER].
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Anatomy↗
Mechanisms of chemical injury of 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 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, among others), and 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 xenobiotic chemicals, is the chronic hypersecretion of TSH, which by receptor-mediated events places the rodent thyroid gland at greater risk of developing tumors through a secondary mechanism of thyroid oncogenesis.
Animals↗
[Aspiration biopsy cytology of the thyroid gland: results and critical evaluation (author's transl)].
Thyroid aspiration biopsy is a valuable complementary method for the examination of an enlarged thyroid gland--especially of cold nodules. Undifferentiated tumours and papillary carcinomas can be recognized with great accuracy. The inability to achieve a precise distinction between atypical follicular adenoma and highly-differentiated follicular carcinoma leads to false-positive or false-negative findings--depending on the strategy of cytological evaluation used. The selective value of the method can be preserved only by accepting false-positive cytological findings; false-negative findings are rare. Aspiration biopsy and cytological examination of the thyroid gland, therefore, can make a valuable contribution towards obtaining a precise indication for the surgical treatment of cold nodules of the thyroid.
Adenoma↗
[Standard histopathologic criteria in intraoperative diagnosis of thyroid gland diseases].
The objective of intraoperative histological diagnostics of thyroid gland diseases using the tissue freezing method is planning the appropriate surgical scope at the time of operation. This necessitates maximal diagnostic accuracy having in mind the fact that freezing changes the tissue structure resulting in numerous technical defects in the histological preparation. These defects can be eliminated by multiplying histomorphological criteria, accurate explanation of their significance and interdependency and by making a conclusion in the form of ex tempore diagnosis. We studied 88 cases of ex tempore diagnosed changes in the thyroid gland using 15 different morphological criteria. The adjustment of the metrics scale to arithmetic progression enabled us to use certain number of parametric tests. A universal approach along with non-parametric methods with highly significant results made it possible to evaluate histomorphological criteria which can be regularly used in intraoperative diagnostics of pathological changes in the thyroid gland.
Biopsy↗