S I Grigorakis

Alexandra Regional General Hospital, Athínai, Attica, Greece

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Publications (9)31.98 Total impact

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    ABSTRACT: The aim of the present study was to examine fasting (0') and postglucose glucagon levels in normal and gestational diabetes mellitus (GDM) pregnancy, as available data are somewhat conflicting. To this end we studied 18 women with GDM at 26-32 weeks of pregnancy and compared these with 26 normal pregnant women matched for age and BMI. We also examined glucagon suppressibility postpartum (2-4 months) in the same ex-GDM women, in whom normal glucose tolerance was confirmed (WHO criteria) and compared these with 17 controls matched for age and BMI. Glucose, insulin and glucagon levels were measured during a 100 or 75 g oral glucose tolerance test (OGTT) respectively. In pregnant women, baseline and 3 h after glucose ingestion, plasma glucagon levels were significantly higher (p < 0.05) in women with GDM compared to normal women. Interestingly, in normal pregnancy a significant increase (p < 0.01) of postglucose plasma glucagon levels at 1 and 2 h compared to baseline levels was observed, while there was no change in GDM pregnancy. In postpartum euglycaemic women, there was no difference in basal glucagon levels between the two groups. A differential glucagon response during OGTT was observed: in control women there was a significant glucagon suppression (p < 0.01) at 2 h, while there was a significant glucagon increase (p < 0.01) 1 h after glucose ingestion, in ex-GDM women. We conclude that (a) absence of the suppressibility of glucagon in ex-GDM women with normal OGTT may indicate insulin resistance and might be involved in the natural history towards glucose intolerance; and (b) nonsuppression of glucagon in normal late pregnancy as well as in pregnancy complicated by GDM may be due to "physiological" insulin resistance of the alpha cells during this period.
    Acta Diabetologica 03/2005; 42(1):31-5. · 4.63 Impact Factor
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    ABSTRACT: We have previously reported that amylin/islet amyloid polypeptide (IAPP) mRNA is detected in a substantial subset of medullary carcinomas of the thyroid (MTCs). The aim of this study was to determine if the amylin/IAPP gene is expressed as the IAPP peptide in MTC tissues. In 10 patients with a histological diagnosis of MTC and with persisting or recurrent disease (basal calcitonin levels >250 pg/ml), the fasting serum insulin and plasma glucose, IAPP and calcitonin levels were measured and compared with those of 18 normal control subjects matched for age and body mass index. IAPP expression was studied by immunohistochemistry in MTCs and lymph-node metastasis tissues. Seven of ten MTC patients had abnormally elevated IAPP levels. Plasma IAPP and serum insulin levels were correlated in both patients and controls, but the slope of the regression line was significantly higher for MTC patients. IAPP staining was detected in four out of 12 random MTC samples and in two out of five lymph-node metastases, using immunohistochemistry. These results indicate that MTC cells express IAPP at the peptide level and that this raises the peripheral plasma levels. Further studies may reveal whether this is a feature of malignant disease.
    European Journal of Endocrinology 11/2001; 145(5):585-9. · 3.14 Impact Factor
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    ABSTRACT: This study assessed whether the Trp(64)Arg polymorphism of the beta3-adrenergic receptor (beta3-AR), which has been associated with obesity, insulin resistance, weight gain, and earlier onset of type 2 diabetes, is more frequent in women who develop gestational diabetes mellitus (GDM) or whether it is associated with weight gain during pregnancy A total of 311 Greek pregnant women (180 with GDM and 131 without GDM [control]) who underwent a 100-g oral glucose tolerance test (OGTT) in the third trimester of pregnancy were genotyped for the beta3-AR Arg(64) polymorphism. Insulin levels were also determined during the OGTT. The frequency of Trp(64)Arg heterozygotes in this population was approximately 7% and was similar in the GDM and control groups (6.7 vs. 6.9%) as well as in the obese (BMI > or =27 kg/m2) and the nonobese (6.3 vs. 6.8%) subgroups. In the GDM group, BMI, fasting insulin resistance index, and diastolic blood pressure were significantly higher in Trp(64)Arg carriers; these differences were no longer observed when obesity was considered. In the 4 subgroups (control Trp(64)Trp and Trp(64)Arg and GDM Trp(64)Trp and Trp(64)Arg), a highly significant trend was evident of an increase in the percentage of subjects with shorter height. The frequency of the Arg(64) allele in Greek pregnant women is relatively rare compared with other ethnic groups and is probably not related to the development of GDM or obesity The observed tendency for shorter body height in Arg(64) carriers merits further evaluation in larger population samples.
    Diabetes Care 08/2000; 23(8):1079-83. · 7.74 Impact Factor
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    ABSTRACT: The proopiomelanocortin (POMC) gene whose normal pituitary specific mRNA product is 1200 bases (b) is also expressed in placenta and its peptide derivatives such as ACTH and beta-endorphin may play an important role in the initiation of labor. So far, two mRNA transcripts, one small (800b) and one large (1380b) have been reported in placenta by Northern blot analysis, similar to other endocrine tissues and various extrapituitary tumors; however, it is questionable whether both of these transcripts are effectively translated to a functional protein. We examined by Northern blot analysis the size and the differential expression of placental POMC gene transcripts in pregnant women with different modes of delivery. Placental tissues were collected from two groups of pregnant women, six with vaginal delivery (VD) and five with cesarean section (CS). In both groups of placentae three POMC gene transcripts were detected of 800, 1200 and 1380 bases; the 1200b pituitary specific species often predominated and was always present. The 800b transcript was also always present, while the large transcript (1380b) was expressed in 3/6 VD and 2/5 CS placental tissues. No differences in the relative levels of any of these mRNA species showing effect of the mode of delivery were observed. We conclude that POMC gene transcription in placental tissue at term gives rise to three mRNA transcripts, thus resembling extrapituitary tumors. The reported changes in the levels of the derivative peptides according to the mode of delivery do not reflect changes in POMC mRNA levels and could be attributed to a post-translational effect.
    European Journal of Endocrinology 06/2000; 142(5):533-6. · 3.14 Impact Factor
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    ABSTRACT: Hormonal parameters during the last trimester of pregnancy contribute to a natural increase of insulin resistance. It is not known whether any of these are further involved in the manifestation of gestational diabetes mellitus (GDM) in affected individuals. Basal levels of adrenocorticotropic hormone, cortisol, growth hormone, insulin-like growth factor-I, prolactin, glucagon, estradiol, progesterone, human placental lactogen and human chorionic gonadotropin were investigated in 15 nonobese women with GDM and 26 matched normal pregnant women (N). A linear discriminant analysis was performed to further compare the predictive value of the basal hormone levels. Plasma glucagon levels were significantly higher in the GDM group (p = 0.014); this difference was even higher (p = 0.007) when the number of women was increased (GDM = 33, N = 62). No significant differences were found in the levels of any of the other hormones. It is not clear whether elevated glucagon levels have any involvement in the pathogenesis of GDM or simply reflect the relative insulin deficiency of these women.
    Gynecologic and Obstetric Investigation 02/2000; 49(2):106-9. · 1.10 Impact Factor
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    ABSTRACT: We present the case of a patient in whom we diagnosed two different thyroid carcinomas (one on each lobe) of distinct histologic type: one derived from the follicular cells (papillary) and one from the C cells (medullary). They were both diagnosed preoperatively by fine needle aspiration (FNA), and the diagnosis was confirmed with histologic examination. "Inappropriate" staining with neuroendocrine markers was observed in the papillary tumor. Analysis of tumor tissue for the RET oncogene mutations, commonly found in the MEN2 syndromes, was negative. This case supports the view of a common origin for these two tumor types.
    General & diagnostic pathology 07/1997; 142(5-6):371-4.
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    ABSTRACT: In order to define the islet amyloid polypeptide (IAPP) levels in gestational diabetes mellitus (GDM) and their interrelationship with the insulin levels, we studied (1) the placental RNA from 10 women (5 with GDM and 5 normals) for IAPP expression by Northern blotting and (2) 10 women with GDM during a 100-gram oral glucose tolerance test and compared these with 11 normal women matched for obesity and age. Plasma levels of glucose, IAPP, insulin, and C peptide were determined. No IAPP expression was detected in any of the placentae after a long exposure. We could not demonstrate any differences in plasma IAPP levels (basal or stimulated) between the two groups of pregnant women. However, in women with GDM we found a lower IAPP/insulin ratio (p < 0.05) and a lower maximal IAPP/maximal insulin response ratio during the oral glucose tolerance test (p < 0.05) than in normal women. Therefore, IAPP does not appear to be directly involved in the development of GDM. The peripheral levels of IAPP relative to insulin are lower in GDM, a finding similar to that described in type 2 diabetes mellitus (non-insulin-dependent diabetes mellitus). This observation further confirms that GDM resembles the early stages of type 2 diabetes mellitus.
    Gynecologic and Obstetric Investigation 01/1997; 44(1):6-10. · 1.10 Impact Factor
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    ABSTRACT: Whether the differences in renal function found in vegetarian compared with omnivorous subjects are related to quantity or quality of the protein is unknown. We have studied the renal function of nine normotensive, nonproteinuric type I diabetic patients who were fed in random order for 4 weeks either an animal protein diet (APD) (protein intake 1.1 g . kg-1 . day-1) or a vegetable protein diet VPD (protein intake 0.95 g . kg-1 . day-1). The two diets were isocaloric. In a crossover study, we measured glomerular filtration rate (GFR) (inulin clearance), renal plasma flow (RPF) (p-aminohippurate clearance), plasma amino acids, growth hormone, glucagon, insulin-like growth factor I-(IGF-I), and microalbuminuria. GFR and RPF were lower with the VPD than with the APD (89.9 +/- 4.1 vs. 105.6 +/- 5.1 ml . min-1 . 1.73 m-2, P < 0.05, and 425.7 +/- 22.2 vs. 477.8 +/- 32.2 ml . min-1 1.73m-2, P < 0.05, respectively). Renal vascular resistance (RVR) was higher with the VPD than with the APD (101 +/- 25 vs. 91 +/- 10 mmHg . min-1 . ml-1, P < 0.05). Filtration fraction (FF) remained unchanged after either diet. Fractional clearance of albumin fell with the VPD to 2.0 +/- 0.65 from 3.4 +/- 1.15 x 10-6 (P < 0.05). At the end of the APD and VPD, the plasma levels of growth hormone and glucagon did not differ significantly. Plasma levels of IGF-I were higher with the APD than with the VPD (1.1 +/- 0.6 vs. 0.9 +/- 0.13 U/ml, P < 0.05). Plasma concentrations of valine and lysine were significantly higher with the APD than with the VPD (234.6 +/- 30.3 vs. 164.5 +/- 25.4 mm1/1, P < 0.05, and 565 +/- 45.1 vs. 430 +/- 56.1 mmol/l, P < 0.05, respectively), whereas plasma valine was strongly correlated to the GFR (r = 0.832, P < 0.01). No differences were found in other amino acids. A VPD has significantly different renal effects from an APD equal in protein intake in normotensive type I diabetic patients. This could be explained partly by differences in plasma concentrations of amino acids and IGF-I.
    Diabetes Care 09/1995; 18(9):1233. · 7.74 Impact Factor
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    ABSTRACT: The amylin/islet amyloid polypeptide (IAPP) gene is the third member of the calcitonin (CT)/calcitonin gene related peptide (CGRP) gene family, which includes the alpha CT/CGRP (CALC-I) and beta CGRP (CALC-II) genes. CT is predominantly expressed in thyroid C cells, alpha and beta CGRP (CGRP-I and II) in neural tissue and amylin/IAPP in pancreatic beta cells. Both the detailed tissue distribution and the physiological role of amylin are subjects of current research. We sought to characterize the RNAs transcribed from the IAPP gene in normal human pancreas and to investigate possible ectopic expression of this gene in neuroendocrine tumours. DESIGN AND TISSUES: RNA was extracted from normal human pancreas, five phaeochromocytomas and 12 medullary thyroid carcinomas (MTCs) and studied by Northern blotting. We found that in normal human pancreas the IAPP gene transcripts differ in size from those reported for human insulinoma. Expression of the amylin/IAPP gene was detected in seven of the MTCs, while it was not detected in phaeochromocytomas. There were no apparent clinical or histological differences between IAPP positive and IAPP negative MTCs. The relative expression levels of the four mRNAs of the CT/CGRP gene family varied between the different tumours. Our findings are consistent with the view that ectopic hormone production may occasionally be causally related to the common origin of related genes. The possibility that IAPP may constitute a minor component of MTC amyloid should be considered.
    Clinical Endocrinology 08/1994; 41(1):21-6. · 3.40 Impact Factor