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Nikolaos Pontikides

Publications and source records attributed to Nikolaos Pontikides.

7 recordsLinked to original sources
PubMed2005

Resistin levels in hyperthyroid patients before and after restoration of thyroid function: relationship with body weight and body composition.

BACKGROUND: Resistin is a recently discovered peptide hormone that belongs to a family of tissue-specific resistin-like molecules. To date, very few studies have reported on resistin concentrations in hyperthyroid patients, and they present controversial results. OBJECTIVES: To undertake a controlled, prospective study to investigate resistin concentrations in hyperthyroidism before and after restoration of euthyroidism and to correlate the results with body weight, body fat, waist circumference and body mass index (BMI). PATIENTS AND METHODS: A total of 43 hyperthyroid patients (12 men and 31 women) were investigated, in addition to 23 controls. Anthropometric parameters and resistin concentrations were measured. All the patients commenced taking antithyroid drugs and 3-4 months later the same investigations were performed in 36 of the 43 individuals. RESULTS: Hyperthyroid patients exhibited increased resistin concentrations in comparison with controls. Normalization of thyroid hormones was accompanied by a significant decrease in resistin concentration. A sex difference was also found, men showing a significant decrease in resistin concentrations, whereas in women no such difference was found. Resistin concentrations did not correlate with different anthropometric parameters, age and thyroid hormones, either before or after treatment. CONCLUSIONS: This study demonstrates for the first time that, although resistin concentrations are increased in hyperthyroidism, they are not associated with body weight, body fat, waist circumference or BMI, which makes it unlikely that resistin plays a crucial part in thermogenesis and energy homeostasis in thyrotoxic patients.

Adult↗
PubMed2004

Male reproductive function in relation with thyroid alterations.

Despite the high prevalence of thyroid diseases in the general population, the impact of the latter on male reproductive function has been the subject of only a few well-controlled clinical studies. Hyperthyroidism appears to cause alterations in the sex steroid hormone metabolism as well as in spermatogenesis and fertility. Sperm motility is mainly affected. These abnormalities reverse after restoration of euthyroidism. The effects of hypothyroidism on male reproduction appear to be more subtle than those of hyperthyroidism and reversible. Severe juvenile hypothyroidism may be associated with precocious puberty. Hypothyroidism in adults is associated with disturbances in the sex steroid hormone metabolism as well as infertility, although available data concerning the latter are scarce. Radioiodine ((131)I) treatment for dfferentiated thyroid cancer may cause transient impairment of testicular function Gonadal damage may be cumulative in those requiring multiple administrations and sperm banking should be considered in such patients.

Animals↗
PubMed2004

Consequences of an intracranial germ cell-tumor in a young adolescent.

Germ cell tumors (GCTs) are relatively rare tumors, which arise in patients of all ages. They are most common in the first and second decades of life with a male predominance. The most frequent tumors arise in the pineal and suprasellar region. The long-term consequences of these tumors have not been very well characterized, as few series with a limited number of patients have reported on the neuro-endocrine development and quality of life of these young people. In this communication we present a male patient who was diagnosed clinically in 1998 at the age of 17 years to have a GCT and subsequently treated with radiotherapy. Today, 6 years after the initial diagnosis his neuro-endocrine and neuro-cognitive outcomes are quite good, while his quality of life is poor mainly due to many psychological problems that he experiences in his every day life. However, it has to be noted that 6 years is insufficient follow-up to assess late post radiation effects.

Adolescent↗
PubMed2003

Extramedullary hemopoiesis in a thyroid nodule with extensive bone metaplasia and mature bone formation.

Thyroid nodules may undergo a wide range of degenerative change such as infarction, hemorrhage, or fibrosis, which may be localized or extensive and associated with calcification or even ossification. However, the detection of true bone formation in a thyroid nodule is a very rare occurrence. Extramedullary hemopoiesis (EMH) has been described in almost every organ of the body, mainly in tissues active in hemopoiesis in embryonic life. It is extremely rare for EMH to occur in the thyroid gland especially in patients without known chronic anemia. We describe a case of a cold thyroid nodule with histologically proven extensive bone metaplasia and formation of mature bone with foci of hemopoietic tissue in a young woman without chronic anemia, which, to the best of our knowledge, is the first to be reported in the English language literature.

Adult↗
PubMedDate not supplied

The effect of long-term somatostatin analogue treatment on free and total insulin-like growth factor (IGF) -I, -II and IGF binding protein -1, -2 and -3 serum levels in euthyroid patients with active thyroid eye disease.

The aim of this study was to investigate the effect of long-term somatostatin analogue (SM-a) treatment on serum levels of free (F) and total (T) insulin-like growth factor (IGF)-I, -II and IGF binding protein (IGFBP) - 1, -2 and -3 in euthyroid patients with active thyroid ophthalmopathy. For this purpose, we measured the above-mentioned parameters in 21 patients (11M, 10F), aged 50.8+/-11.8 years (range 35-70) and 19 healthy individuals matched for age, gender and body mass index (BMI). A total of 4 SM-a (sandostatin LAR((R))-30) injections, each monthly, were administered in each patient and measurements were performed prior to treatment and 20-30 days after the last injection, while in control individuals the same determinations were performed only once. All patients had active thyroid eye disease (TED), with clinical activity scores (CAS) >/= 4 (5.3+/-1.1) and positive orbital octreoscan in both eyes. Serum F and T IGF-I and IGF-II were determined using non-competitive, time-resolved monoclonal immunofluorometric assays. IGFBP-1 and IGFBP-2 were determined by an in-house radioimmunoassay, while IGFBP-3 by commercially available IRMA. Our results showed that F and T IGF-I, -II and IGFBP-1, -2 and -3 levels in patients before and after administration of SM-a were comparable and the levels did not differ significantly from those of controls. Furthermore, no statistically significant differences emerged in the ratio between molar weights of TIGF-I/IGFBP-3 and TIGF-II/IGFBP-3, as well as in the ratio of F/TIGF-I and F/TIGF-II in patients before and after SM-a therapy. Fourteen patients (66%) experienced a decline in CAS of at least >1 point in each eye after SM-a administration, whereas in the remaining the CAS did not change. Finally, no relationship was found between the levels of the above-mentioned parameters (post therapy) and CAS, octreoscan scores and thyroid hormones levels. In conclusion, we showed that although SM-a administration in euthyroid patients with active TED had a beneficial effect in a significant percentage of patients, this effect was not associated with a decline in the circulating IGF-I, -II and IGFBP-1, -2 and -3 levels, at least under the conditions of the present study. It can be postulated that if the mechanism of action of SM-a is through reduction of IGF-I levels, this effect is possibly exerted in the retrobulbar tissues by local paracrine/autocrine action.

Journal Article↗
PubMedDate not supplied

Influence of cigarette smoking on thyroid function, goiter formation and autoimmune thyroid disorders.

Both smoking and thyroid dysfunction are frequent in the general population. Many studies have shown that cigarette smoking interferes with thyroid function and with the evolution of thyroid pathology (e.g. goiter formation and thyroid cancer development). Some studies have also suggested a significant correlation of Graves' hyperthyroidism and Graves' ophthalmopathy with the severity of smoking. In addition, cigarette smoking may reduce the effectiveness of some therapeutic modalities, such as orbital radiotherapy or high-dose systemic glucocorticoid administration for severe thyroid eye disease. Tobacco smoking seems to induce similar changes in thyroid function in the adult and the fetus. This review article discusses the effect of cigarette smoking on thyroid function and morphology as well as on thyroid autoimmunity.

Journal Article↗