Alexandra Margeli
Boston Children's Hospital
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Featured researches published by Alexandra Margeli.
Psychoneuroendocrinology | 2007
Panagiota Pervanidou; Gerasimos Kolaitis; Stella Charitaki; Alexandra Margeli; Spyros Ferentinos; Chrysa Bakoula; Christina Lazaropoulou; Ioannis Papassotiriou; John Tsiantis; George P. Chrousos
BACKGROUND This study examined prospectively the activity of the hypothalamic-pituitary-adrenal axis, the sympathetic nervous system and inflammatory factors in children shortly after a motor vehicle accident (MVA) in relation to later posttraumatic stress disorder (PTSD) development. PATIENTS AND METHODS Fifty six children, aged 7-18, were studied after an MVA and 1 and 6 months later; 40 subjects served as controls. Morning serum cortisol and interleukin (IL)-6 and plasma catecholamine concentrations were measured within 24h after the event. Salivary cortisol was measured 5 times at defined time points during the same day. PTSD diagnoses 1 and 6 months later were based on K-SADS interview. RESULTS Morning serum IL-6 concentrations, measured within the first 24h after the accident, were higher in children that developed PTSD 6 months later than those who did not and those of the control group. Longitudinal IL-6 measurements revealed normalization of IL-6 in the PTSD group, while no differences between the three groups were detected 1 and 6 months later. Evening salivary cortisol and morning serum IL-6 after the accident were positively inter-related (r=0.54, p<0.001) and in separate regression analyses both predicted PTSD development 6 months later. In contrast, morning serum IL-6 did nor correlate with morning serum or salivary cortisol concentrations. CONCLUSIONS Immediate posttraumatic alterations in neuroendocrine or inflammatory factors-increased evening salivary cortisol and/or increased morning serum IL-6 concentrations-are involved in subsequent PTSD development in children and adolescents.
International Journal of Biological Markers | 2003
Stamatios Theocharis; Alexandra Margeli; Antonios Koutselinis
The metallothionein (MT) family is a class of low molecular weight, intracellular and cysteine-rich proteins presenting high affinity for metal ions. Although the members of this family were discovered nearly 40 years ago, their functional significance remains obscure. Four major MT isoforms, MT-1, MT-2, MT-3 and MT-4, have been identified in mammals. MTs are involved in many pathophysiological processes such as metal ion homeostasis and detoxification, protection against oxidative damage, cell proliferation and apoptosis, chemoresistance and radiotherapy resistance. MT isoforms have been shown to be involved in several aspects of the carcinogenic process, cancer development and progression. MT expression has been implicated as a transient response to any form of stress or injury providing cytoprotective action. Although MT participates in the carcinogenic process, its use as a potential marker of tumor differentiation or cell proliferation, or as a predictor of poor prognosis remains unclear. In the present review the involvement of MT in defense mechanisms to toxicity and in carcinogenicity is discussed.
Fertility and Sterility | 2010
Sophia Sakka; Dimitrios Loutradis; Christina Kanaka-Gantenbein; Alexandra Margeli; Maria Papastamataki; Ioannis Papassotiriou; George P. Chrousos
OBJECTIVE To investigate the metabolic profile, traditional adipokines, and indices of insulin resistance and low-grade inflammation in children born as a result of IVF compared with spontaneously conceived controls. DESIGN Cross-sectional, case-control study. SETTING IVF Section of the First Department of Obstetrics and Gynecology and the First Department of Pediatrics of the University of Athens. PATIENT(S) One hundred six children conceived after classic IVF and 68 age-matched spontaneously conceived controls, aged 4-14 years. INTERVENTION(S) Children underwent physical examination and morning fasting samples were collected. MAIN OUTCOME MEASURE(S) Lipid profile, circulating fasting glucose, insulin, leptin, adiponectin, high-sensitivity interleukin-6, and high-sensitivity C-reactive protein were determined and the fasting glucose-to-insulin ratio was calculated. RESULT(S) Children born as a result of classic IVF had significantly higher systolic and diastolic blood pressures (BP) and triglycerides than controls. These BP differences remained significant even after correction for birth size and multiple births. No significant differences in biochemical indices of insulin resistance, circulating adipokines, and inflammatory markers were detected before or after these same corrections. CONCLUSION(S) Despite an increase of BP, children born as a result of IVF have no biochemical evidence of insulin resistance, including fasting glucose-to-insulin ratio and circulating adipokines, or low-grade chronic inflammation. However, the long-term impact of periconceptual manipulations should be closely monitored.
Angiogenesis | 2003
Alexandra Margeli; Gregory Kouraklis; Stamos Theocharis
The peroxisome proliferator activated receptor (PPAR)-γ ligands have been initially described as important regulators of adipogenic differentiation and glucose homeostasis. Detailed studies in different tissues pointed to the roles of these ligands in cell proliferation and cancer, establishing their anticancer properties against a wide variety of neoplastic cells. The growth of any solid tumor depends on angiogenesis, as tumor vascularization is a vital process for tumor volume increase and its metastatic potential. Recently, the role of PPAR-γ ligands as potent angiogenesis modulators in vitro and in vivo, has been referred. This review takes into consideration the latest data concerning the participation of PPAR-γ ligands in the biological mechanisms underlying angiogenesis inhibition (important in anticancer therapy) and the controversy concerning angiogenesis induction (important in non-neoplastic diseases). As inhibition of angiogenesis represents one of the more promising, new approaches to anticancer therapy, PPAR-γ ligands in addition to their established role as tumor cell cycle modulators could be implicated in future strategies for cancer treatment.
European Journal of Endocrinology | 2008
Marialena Kyriakakou; Ariadne Malamitsi-Puchner; Helen Militsi; Theodora Boutsikou; Alexandra Margeli; Demetrios Hassiakos; Christina Kanaka-Gantenbein; Ioannis Papassotiriou; George Mastorakos
OBJECTIVE Leptin and adiponectin are two adipocytokines that play a critical role in the control of energy balance and metabolism as well as in conditions, such as insulin resistance, inflammation, and the development of the metabolic syndrome in adult life. Leptin has been associated with asymmetric intrauterine growth restriction (IUGR). The aim of this study was to investigate the perinatal implication of leptin and adiponectin in IUGR. Design Leptin and adiponectin were measured in the plasma of 40 mothers, in the umbilical cord (UC) blood of their 20 appropriate for gestational age (AGA) and 20 IUGR singleton, full-term fetuses, and neonates on day 1 (d1) and day 4 (d4) of life postnatally. METHODS Serum leptin and adiponectin levels were measured by RIA. Serum cortisol levels were measured with an electrochemiluminescence immunoassay. RESULTS Leptin and adiponectin serum levels were higher and lower respectively in IUGR (mean+/-s.e.m., 32.5+/-3.8 and 5.4+/-0.9 mug/l respectively) compared with AGA (20.4+/-2.1 and 11.8+/-1.3 mug/l respectively) mothers (P<0.05), although body mass index did not differ between these two groups. Leptin levels positively correlated with adiponectin levels in the AGA (r=0.547, P<0.05) but not in the IUGR mothers. UC, d1, and d4 leptin and adiponectin levels did not differ between IUGR and AGA groups. UC were significantly higher than d1 leptin levels (P<0.05) in the IUGR group but not in the AGA group. CONCLUSIONS The increased UC leptin levels compared with d1 in IUGR fetuses might be directly and/or indirectly related to the subsequent development of insulin resistance in these neonates. This pathologic situation seems to be related to a specific profile of increased leptin and decreased adiponectin levels in IUGR mothers indicating a genetic predisposition for the development of insulin resistance.
Lung Cancer | 2002
Stamatios Theocharis; Helen Kanelli; Ekaterini Politi; Alexandra Margeli; Christos Karkandaris; Theodoros Philippides; Antonios Koutselinis
Peroxisome Proliferator Activated Receptor-gamma (PPAR-gamma) is a ligand-activated transcription factor belonging to the steroid receptor superfamily. It is a key regulator of adipogenic differentiation and glucose homeostasis, the ligands of which have also been demonstrated to induce differentiation in human breast, lung and colon cancer cell lines. In the present study, PPAR-gamma expression in cases of non-small cell lung carcinoma (NSCLC) was examined immunohistochemically and was correlated with tumor histological type and grade. Primary tumor samples from 147 patients with NSCLC were immunostained using a monoclonal antibody against PPAR-gamma. Positive PPAR-gamma immunostaining was prominent in 61 out of 147 cases (42%) and negative in the rest. PPAR-gamma positivity was prominent in 37 out of 79 cases (47%) of squamous cell lung carcinoma and in 24 out of 68 ones (35%) of lung adenocarcinoma. PPAR-gamma positivity was most frequently observed in squamous cell tumors (P=0.021) and in tumors of high histological grade of both histological types (P=0.041). Well-differentiated adenocarcinoma cases presented increased frequency for PPAR-gamma positivity compared with moderately and poorly differentiated ones (P=0.001). The intensity and pattern of PPAR-gamma staining in tumor cells were not correlated with histopathological parameters in PPAR-gamma positive cases of NSCLC examined. Our findings support evidence for participation of this protein in the biological mechanisms underlying the carcinogenic evolution in the lung, suggesting also the importance of specific PPAR-gamma ligands as future therapeutic approach in lung cancer.
Digestive Diseases and Sciences | 1994
Stamatios Theocharis; Antigone S. Skopelitou; Alexandra Margeli; Kitty J. Pavlaki; Christos Kittas
Proliferating cell nuclear antigen (PCNA) is a nuclear protein maximally elevated in the S phase of proliferating and transformed cells and is recognized by the monoclonal antibody PC-10 in paraffin tissue sections. The liver regenerative process after partial hepatectomy in rats was estimated with thein vivo incorporation of [3H]thymidine into liver DNA and the liver thymidine kinase activity. The expression of PCNA in rat liver after partial hepatectomy was performed by immunohistochemical staining with PC-10 in paraffin embedded tissues, at different time intervals up to 240 hr. Proliferating cell nuclear antigen expression, [3H]thymidine incorporation into DNA, and liver thymidine kinase activity exhibited marked oscillations during the liver regenerative process. A close relationship was demonstrated among DNA synthesis, thymidine kinase activity, and PC-10 score. Our results suggest that PC-10 monoclonal antibody may be used as a worthwhile proliferation index in the evaluation of the rate of liver regeneration in rats.
Clinical Chemistry | 2008
Christina Kanaka-Gantenbein; Alexandra Margeli; Panagiota Pervanidou; Sophia Sakka; George Mastorakos; George P. Chrousos; Ioannis Papassotiriou
BACKGROUND although there is much evidence regarding the physiologic and pathogenic roles of the newly described adipokines retinol-binding protein 4 (RBP4) and lipocalin-2 as potential promoters of insulin resistance in obese adults, relatively little information exists regarding their roles in obese children. METHODS we investigated the circulating concentrations of RBP4 and lipocalin-2 in 80 obese girls (ages 9- 15 years) and their relationships with high-sensitivity C-reactive protein (hs-CRP) and the adipokines leptin and adiponectin. We divided participants by their body mass index standard deviation scores (BMI SDSs) into 4 groups of 20 girls each: overweight [mean BMI SDS (SD), 1.8 (0.4)], obese [2.2 (0.4)], morbidly obese [3.6 (0.4)], and lean controls [-0.11 (0.4)]. We measured plasma-soluble RBP4, the RBP4-binding protein transthyretin, lipocalin-2, hs-CRP, leptin, and adiponectin and calculated the homeostatic assessment model (HOMA) index from fasting glucose and insulin concentrations. RESULTS unexpectedly, plasma RBP4 and lipocalin-2 concentrations were correlated negatively with BMI SDS values (P = 0.005, and P < 0.03, respectively). These results were different from those of adults and were not correlated with the HOMA index. In contrast, hs-CRP and leptin concentrations were positively correlated with BMI SDS values (P < 0.0001, and P < 0.00001, respectively), as expected, whereas the adiponectin concentration was negatively correlated (P = 0.008). CONCLUSIONS although the correlations of leptin, adiponectin, and hs-CRP concentrations with BMI in children are similar to those of adults, the correlations of RBP4 and lipocalin-2 with BMI in children are the inverse of those observed in adults. Thus, although systemic inflammation and mild insulin resistance are present in childhood obesity, RBP4 and lipocalin-2 concentrations are not increased in children as they are in obese adults with long-standing severe insulin resistance and type 2 diabetes.
Toxicology | 2001
Stamatios Theocharis; Alexandra Margeli; Spyridon D. Skaltsas; Chara Spiliopoulou; Antonios Koutselinis
Metallothioneins (MTs), are low molecular weight proteins, mainly implicated in metal ion detoxification. In the present study, we investigated the expression of hepatic MT in a rat model of injury and regeneration, induced by carbon tetrachloride (CCl(4)) administration. A single intraperitoneal injection of 1 ml CCl(4)/kg body weight was performed in male Wistar rats, killed at different time points post-administration. The enzymatic activities of aspartate and alanine aminotransferases in serum were determined, in addition to the liver histological findings, to estimate hepatotoxicity. The rate of tritiated thymidine incorporation into hepatic DNA, the enzymatic activity of thymidine kinase in liver tissue and the assessment of the mitotic index in hepatocytes, were used as indices of regeneration. MT was detected immunohistochemically in liver tissue sections. CCl(4) administration caused severe hepatic injury, followed by regeneration. MT expression became prominent as early as 12 h after the administration of CCl(4), in the nuclei of hepatocytes, while at 24 and 36 h intense cytoplasmic staining for MT appeared in the hepatocytes in the vicinity of necrotic areas. The peak of hepatocyte proliferative capacity, occurring at 48 h post-CCl(4) administration coincides with the maximum nuclear and cytoplasmic MT expression. At further time points MT expression presented a decreasing trend. Induction of MT expression was observed in the liver after a single administration of CCl(4), being more prominent at the time of maximum hepatocellular proliferation, participating actively in the replication of hepatocytes.
Digestive Diseases and Sciences | 2003
Stamatios Theocharis; Lila Papadimitriou; Zoi P. Retsou; Alexandra Margeli; Sotirios Ninos; John D. Papadimitriou
It has previously been shown that recombinant granulocyte-colony stimulating factor (rG-CSF) accelerates and enhances hepatocyte proliferation in partially hepatectomized rats. In the present study, we examined the effect of rG-CSF administration on liver injury, regeneration, and survival outcome in an experimental rat model of fulminant hepatic failure (FHF) and encephalopathy induced by repeated injections of thioacetamide (TAA). FHF was induced in adult male Wistar rats by three consecutive intraperitoneal injections of TAA, at intervals of 24 hr. The animals were also injected with either saline or rG-CSF. Serum biochemical parameters and blood ammonia levels, liver histology, stage of hepatic encephalopathy, and survival were statistically significantly improved in TAA-intoxicated and rG-CSF-treated rats compared to TAA-intoxicated and saline-treated ones. Furthermore, rG-CSF not only ameliorated the histologically evident liver injury in a statistically significant manner but also enhanced the proliferative capacity of the hepatocytes. Our data confirm the beneficial effect of rG-CSF administration in this animal model of FHF and encephalopathy, supporting evidence for a possible use of rG-CSF as supportive therapy in the management of FHF.