Biomedical subjects

Evangelia Zapanti

Publications and source records attributed to Evangelia Zapanti.

7 recordsLinked to original sources

PubMed2006

Pheochromocytoma: physiopathologic implications and diagnostic evaluation.

Pheochromocytoma (PHEO) is a chromaffin cell tumor embryologically arising from the neural crest tissue. The dominant secretory products of PHEO are catecholamines: noradrenaline (norepinephrine), adrenaline (epinephrine), and to a lesser extent dopamine. In addition to catecholamines, PHEO cells also elaborate and release several neuropeptides and inflammatory cytokines which can exert intra-adrenal and extra-adrenal systemic effects and cause characteristic clinical syndromes. In a concise review we present the intra-adrenal and extra-adrenal pathophysiologic implications of PHEO and the nuclear medicine modalities that permit functional imaging of physiological processes and help localize these tumors. The specific pathways of synthesis, metabolism, and inactivation of catecholamines (of PHEOs and paragangliomas) can be used as means to develop suitable tracers for positron emission tomography (PET) ligands. In this review we focus on imaging with PET using [(18)F]-fluorodopamine, [(18)F]-fluorohydroxyphenylalanine, [(11)C]-epinephrine, or [(11)C]-hydroxyephedrine and examine how functional imaging can often complement traditional anatomical imaging modalities and other scintigraphic techniques.

Animals↗

PubMed2006

Treatment options of polycystic ovary syndrome in adolescence.

The polycystic ovary syndrome (PCOS) is defined as a syndrome of hyperandrogenism and chronic anovulation in the absence of other underlying pituitary or adrenal disorders. PCOS often presents in adolescence and is the commonest cause of menstrual disorders and hirsutism. Premature adrenarche and hirsutism that occur before puberty have been associated with PCOS. The etiology of the syndrome is as yet uncertain. Theories have focused on intrinsic defects in the ovarian and adrenal steroidogenesis, and on the role of insulin resistance in modifying reproductive function. Insulin resistance associated with PCOS confers a markedly increased risk of impaired glucose tolerance and type 2 diabetes mellitus in adolescent girls, as in premenopausal women. Therapeutic considerations focus on the management of menstrual irregularities and hyperandrogenism, as well as on the prevention of the metabolic consequences of the syndrome.

Adolescent↗

PubMed2005

Preliminary report: psychological assessment of Greek women with diabetes during pregnancy.

23 Greek pregnant women with type 1 diabetes had a higher mean score on the Maudsley Obsessive-Compulsive Inventory in the second and third trimesters of pregnancy than 13 women with gestational diabetes. Long-term changes in the lifestyle of the former may apparently lead to this higher mean. For those with gestational diabetes, higher scores of alexithymia were correlated with slightly worse glycemic control.

Adult↗

PubMedDate not supplied

The hypothalamic-pituitary-adrenal axis in the neuroendocrine regulation of food intake and obesity: the role of corticotropin releasing hormone.

The aim of this paper is to review the present knowledge on the role of the hypothalamic-pituitary-adrenal axis in the control of food intake and the pathogenesis of obesity and to discuss, on the basis of available literature, the interactions between other neurosystems and this hormonal axis. Food intake is influenced by a system of physiologic signals and behavioral controls consisting of positive and negative sensory feedback mechanisms. It is regulated by a complex neuroendocrine system consisting of peripheral signals (cortisol, leptin) in constant interplay with central neurosystems such as the cocaine-amfetamine-regulated transcript system. In these neurosystems, corticotropin-releasing hormone, pro-opiomelanocortin, melanin-concentrating hormone and neuropeptide Y are actively involved. The corticotropin-releasing hormone system is widely distributed throughout the brain, but it is particularly abundant in the medial parvocellular division of the paraventricular nucleus. Within the brain corticotropin-releasing hormone with its two receptor types, its binding protein and its closely related peptide urocortin forms a network of neuronal pathways capable of interacting with other circuitries controlling food intake and sympathetically-mediated thermogenesis. A defect in the synthesis and release of corticotropin-releasing hormone has been implicated in the development of obesity in laboratory animals. This condition is alleviated by exogenous corticotropin-releasing hormone treatment. The relationship between the neuropeptide Y system and the hypothalamic-pituitary-adrenal axis is complex and seems to include positive feedback between neuropeptide Y and corticosteroids and negative feedback between corticotropin-releasing hormone and neuropeptide Y. Leptin is involved in the regulation of energy balance by interacting with the hypothalamic-pituitary-adrenal axis. In the past, we have shown by cross-correlation analysis, that under physiological conditions cortisol and plasma leptin levels are related to each other in a time-related negative and positive fashion over 24h.

Adrenal Glands↗

PubMedDate not supplied

Effects of GH and IGF-I on the in vitro maturation of mouse oocytes.

OBJECTIVE: A number of hormones and growth factors have been reported to affect the in vitro maturation of oocytes. Their exact effects on follicular growth and oocyte maturation and the mechanisms involved are still unclear. In the present study, we have investigated the effects of Growth Hormone (GH) and Insulin-like Growth Factor 1 (IGF-1) on the in vitro maturation of mouse oocytes. DESIGN: Immature preovulatory oocytes without cumulus cells (denuded), were obtained from 4- to 8-week old female mice and were cultured in Ham's F-10 medium. GH and IGF-1 were added separately or in combination in gradually increasing concentrations in the culture media, while medium-only containing samples were employed as controls. Oocyte development was assessed daily for three days and maturation was considered to be completed when the first polar body appeared. RESULTS: In control samples, 44+/-3% (mean+/-SE) of denuded oocytes formed a polar body. The achieved maturation rate after the addition of either GH or IGF-1 or GH plus IGF-1 was significantly higher than in controls. The highest maturation rates were achieved after the addition of 0.2 microg/ml GH (76%+/-5%), 50 ng/ml IGF-1 (69%+/-5%) and a combination of 0.2 microg/ml GH plus 10 ng/ml IGF-1 (75%+/-5%). CONCLUSIONS: The data suggest that GH and IGF-1, alone or in combination, affect mouse oocyte maturation significantly. The lack of a synergistic effect on oocyte cultures when both hormones were added indicates that both hormones act through the same signaling pathway.

Analysis of Variance↗

PubMedDate not supplied

Estradiol and progesterone supplementation during luteal phase improved the receptivity of the endometrium in a patient with a history of diethylstilboestrol exposure in-utero.

BACKGROUND: Diethylstilboestrol (DES) exposure in-utero has been shown to have negative effects on pregnancy. DES-exposed women are at increased risk of early spontaneous pregnancy loss, ectopic gestation and infertility. DESIGN: A 34-year old woman with a 6-year history of primary infertility is presented. The patient underwent in vitro fertilization (IVF) treatment without success. To improve the quality of the endometrium following IVF treatment, E2 and progesterone supplementation was added to the usual therapeutic regimen. The pregnancy progressed uneventfully and a normal female was born. CONCLUSIONS: This case indicates that the administration of E2 and progesterone in DES-exposed women might improve endometrium receptivity and consequently pregnancy outcome.

Adult↗

PubMedDate not supplied

Insulin resistance in pheochromocytoma improves more by surgical rather than by medical treatment.

Pheochromocytoma, a neuroendocrine tumor, is often associated with hyperglycemia. To investigate the underlying pathogenetic mechanisms, five patients (3 women and 2 men, aged 49+/-2.5, mean+/-SD) with benign adrenal pheochromocytoma were studied with an oral glucose tolerance test (OGTT) and the euglycaemic clamp technique. They were studied preoperatively without taking any medication (stage I), after taking an alpha adrenergic receptor blocking agent (stage II), after taking both an alpha and a beta adrenergic receptor blocking agent (stage III), and after surgical removal of the tumor (stage IV). Before any treatment, fasting blood glucose levels and glucose levels during the OGTT were pathologic in all patients. In all patients, mean glucose levels of the OGTTs performed at the three preoperative stages of the study were significantly higher than those of the OGTT performed postoperatively (ANOVA, alpha<0.05). Insulin levels during the OGTTs performed preoperatively peaked at 90 min while postoperatively they peaked at 60 min. No statistically significant difference was found among mean insulin levels during the OGTTs performed at all stages of the study. The clamp-based insulin sensitivity index (SI) improved progressively from stage I to IV of the study (ANOVA, alpha<0.05) (SIs of stages I, II, III, and IV were, respectively, 3.23+/-0.9 (mean+/-SE), 3.79+/-0.7, 4.67+/-0.3, 6.38+/-1 (10(-4) dl/kg x min per microU/ml)). In conclusion, the pheochromocytoma-associated metabolic alterations of glucose homeostasis improved substantially only after removal of the tumor. The administration of alpha and beta adrenergic receptor blocking agents resulted in a slight but statistically significant improvement in glucose utilization whereas it completely normalized the cardiovascular manifestations of the disease. Thus, it is possible that either the dose of the adrenergic receptor blocking agent needed to control cardiovascular manifestations of pheochromocytoma is different than that needed for glucose metabolism normalization, or that other pheochromocytoma-associated factors may influence directly and/or indirectly carbohydrate homeostasis.

Journal Article↗