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I Georgiou

Publications and source records attributed to I Georgiou.

At least 19 recordsLinked to original sources
PubMed2005

Combined estrogen receptor alpha and estrogen receptor beta genotypes influence the age of menarche.

BACKGROUND: Age at menarche has a strong genetic influence. We reported recently an association between the XbaI (351A-->C)and PvuII (397T-->C) polymorphisms of the estrogen receptor (ER)alpha gene with the age of menarche in Greek adolescents. In the present study, we examined whether ERbeta genotypes alone, or in combination with ERalpha genotypes, may also influence onset of menarche. METHODS: We performed genotyping for the single nucleotide polymorphisms 1730A-->G and 1082G-->A of the ERbeta gene and examined their association with the age of menarche in the same cohort of 145 Greek girls. We then looked for a possible effect of combined ERalpha and beta genotypes on the age of menarche. RESULTS: Menarche occurred 7 months later in girls with the AA genotype of the 1730A-->G polymorphism than in girls with the AG genotype (mean +/- SD: 13.23 +/- 1.24 versus 12.66 +/- 1.26 years, respectively; P = 0.005). The 1082G-->A polymorphism was not detected in any of the girls examined. A significant effect of combined ERalpha and beta genotypes was also apparent. Menarche occurred 11 months later in girls bearing the AA/TT,AA (ERalpha, ERbeta) genotypes compared with girls with the CC/CC,AG genotype (13.30 +/- 1.27 nersus 12.41 +/- 1.28 years; P = 0.042). The difference remained significant after adjusting for body mass index (P = 0.034). CONCLUSION: Combined ERalpha and ERbeta polymorphisms may influence the age of menarche.

Adolescent↗
PubMed2005

Association of SHBG gene polymorphism with menarche.

The age of menarche may be subject to hereditary influences but the specific determinants are unknown. Our aim was to investigate the possible association of a functional (TAAAA)n polymorphism in the promoter of the sex hormone-binding globulin (SHBG) gene with the timing of menarche. This polymorphism has been associated with polycystic ovary syndrome (PCOS) and is considered to contribute to SHBG levels. We studied 130 healthy normal-weight adolescent females from a closed community in North-Western Greece. Information on menarche was obtained through interviews. The BMI was recorded. Genomic DNA was isolated from peripheral blood leukocytes for genotyping the TAAAA repeat region. We subdivided our subjects into two groups based on median age of menarche: those with menarche <13 years and those with menarche > or =13 years. Genotype analysis revealed six (TAAAA)n alleles containing 5-10 TAAAA repeats. The distribution of alleles was different in the two groups. Girls with late menarche had more frequently longer TAAAA alleles (>8 repeats), while girls with early menarche had shorter alleles at a greater frequency (P=0.048). The major contribution to early menarche was by the 6 TAAAA repeat allele. Furthermore, carriers of the longer allele genotypes had later menarche (13.24+/-1.15 years) than those with shorter allele genotypes (12.67+/-1.15, P=0.018). These findings provide evidence for a genetic contribution of SHBG gene to the age of menarche.

Adolescent↗
PubMed2005

Efforts to create an artificial testis: culture systems of male germ cells under biochemical conditions resembling the seminiferous tubular biochemical environment.

Induction of meiotic and post-meiotic alterations of male germ cells in vitro has been the target of several research efforts since 1960. However, to date, the establishment of an ideal culture system in which spermatogonial stem cells can be maintained and directed to proliferate and undergo meiosis and complete spermiogenesis does not exist. This is attributed to the difficulties concerning the isolation and purification of defined subpopulations of germ cells and the establishment of male germ cell lines. In addition, there is no adequate knowledge regarding the optimal biochemical conditions that promote the survival and differentiation of germ cells in long-term cultures. This review focuses on the methodologies that have been proved sufficient to achieve differentiation of cultured male germ cells. Furthermore, the factors regulating spermatogenesis and the technical prerequisites to achieve differentiation of cultured male germ cells are described. Finally, the role of in vitro cultures of immature diploid germ cells in the therapeutic management of men negative for haploid cells in their testes and the subsequent potential genetic and epigenetic risks are discussed.

Animals↗
PubMed2004

PGD for autosomal dominant polycystic kidney disease type 1.

Autosomal dominant polycystic kidney disease (ADPKD) is primarily characterized by renal cysts and progression to renal failure. It is a genetically heterogeneous disease, with mutations in the PKD1 gene accounting for the majority of cases. Direct mutation detection for PKD1-linked ADPKD or type 1 is complicated by the large size and complex genomic structure of PKD1. This paper describes a microsatellite marker-based assay for PGD in couples at risk of transmitting ADPKD type 1. During PGD, genetic analysis is carried out on single blastomeres biopsied from preimplantation embryos obtained after IVF, and only embryos unaffected by the disease under investigation are selected for transfer. Single-cell genetic analysis relied on a fluorescent duplex-PCR of linked polymorphic markers followed by fragment length determination on an automated sequencer. The co-amplification of the intragenic KG8 and the extragenic D16S291 marker at the single-cell level was evaluated in pre-clinical tests on lymphoblasts and research blastomeres. The developed assay proved to be efficient (96.1% amplification) and accurate (1.4% allele drop-out and 4.3% contamination), and can be applied in all informative ADPKD type 1 couples. From five clinical cycles carried out for three couples, two pregnancies ensued, resulting in the birth of two healthy children.

Adult↗
PubMed2004

Novel universal approach for preimplantation genetic diagnosis of beta-thalassaemia in combination with HLA matching of embryos.

BACKGROUND: Beta-Thalassaemia results from co-inheritance of two mutant beta-globin alleles. Allogeneic cord blood cell transplantation (CBT) from an HLA-identical sibling donor is an excellent treatment option for beta-thalassaemia. In families with an affected child and willing to have another child, IVF followed by preimplantation genetic diagnosis (PGD) can be applied to exclude affected embryos. Furthermore, healthy embryos could be HLA matched with the affected child so that cord blood from the future newborn can be used to transplant the affected sibling. METHODS: We developed an indirect single-cell HLA typing technique based on the use of a bank of seven microsatellite markers within the HLA locus from which four informative and evenly distributed markers were selected. RESULTS: The methodology was validated in three beta-thalassaemia families having six ovarian stimulation cycles in view of IVF and PGD. Six PGD cycles were performed in two families. On 58 embryos tested, the combined PCR was successful in 54 (93%). Two transfers were done and one clinical pregnancy was obtained. Using confirmatory analysis on 50 embryos, the accuracy for HLA typing was 100%. CONCLUSION: This strategy offers a new therapeutic option for patients with beta-thalassaemia and other monogenic diseases that can be cured with CBT.

Embryo Transfer↗
PubMed2004

Early prenatal diagnosis by celocentesis.

BACKGROUND: Celocentesis is the ultrasound-guided aspiration of fluid from the extra-amniotic cavity at 7-8 weeks of gestation. This paper reports on the clinical application of celocentesis for early prenatal diagnosis. METHODS: Celocentesis was successfully performed in nine pregnancies and 1-2 mL of fluid were obtained after one needle insertion. The indications were prenatal diagnosis of beta-thalassemia or sickle cell disease (n = 6), Marfan syndrome (n = 1) and paternity testing (n = 2). Molecular biological techniques were used to analyze the celomic fluid and this was successfully carried out in all cases. RESULTS: In two cases pregnancy termination was performed at the request of the mother because in one case the fetus was found to have sickle cell anemia and in the second case paternity testing demonstrated that the father was not the woman's husband. In both cases the results were confirmed using the placental samples collected after pregnancy termination. In six of the seven pregnancies with desirable results, amniocentesis was performed at 16 weeks and the results were concordant with those obtained from celocentesis. All pregnancies were uneventful and resulted in the delivery of healthy and appropriately grown babies. CONCLUSION: Celocentesis may be a viable alternative to the currently used tests of chorionic villus sampling and amniocentesis.

Anemia, Sickle Cell↗
PubMed2004

Lack of association of birth size with polymorphisms of two imprinted genes, IGF2R and GRB10.

Little is known about the determinants of birth size variability among individuals. Maternal and nutritional factors have been studied, but familial clustering suggests genetic factors as well. As a first step in testing this hypothesis, we examined common sequence variants in IGF2R and GRB10, two genes involved in the regulation of growth and subject to parental imprinting. The IGF2R gene was scanned with five polymorphisms spanning the coding and 3'-UTR for possible association with birth size in a set of 97 normal newborns in Greece. In addition, a silent SNP in GRB10 exon 2 was similarly tested as an exploratory first step. Birth weight and length were compared between groups of newborns divided according to which allele they had received from heterozygous parents. No significant differences were found between alleles in either gene, examined either by parental origin or in aggregate. Thus, we found no evidence that IGF2R variants modulate intrauterine growth within the normal range. If such variants exist in GRB10, they are not in linkage disequilibrium with the marker studied.

Alleles↗
PubMed2004

Treatment of MDS patients with recombinant human erythropoietin and the role of GSTs.

Glutathione S-transferases (GSTs) are a group of enzymes involved in the detoxification process of carcinogens and other substances. The genes encoding isoenzymes M1 and T1 have "null" alleles, which are polymorphic in humans. Our purpose was to examine whether the GSTM1 and GSTT1 homozygous null genotypes have an impact on the response to recombinant human erythropoietin (rhuEpo) treatment in MDS patients. We analyzed lymphocyte DNA samples from 27 patients with all types of myelodysplastic syndromes (MDS) at the time of diagnosis. All patients were scheduled to receive rHuEpo in doses of 150 u/Kg/day for a period of 12 weeks in order to obtain and maintain stable responses. A multiplex polymerase chain reaction (PCR) was used to genotype both GSTM1 and GSTT1 simultaneously, in responders and non-responders to rhuEpo with respect to various pretreatment parameters: haemoglobin, white blood cell count, platelets, serum erythropoietin, transfusion requirements and bone marrow blasts. The data obtained were evaluated by chi2 test and odds ratio were extracted. Twelve out of 27 evaluated patients demonstrated an erythroid response (44%). Nine out of the 12 patients (75%) responding after 12 weeks of treatment had GSTM1 null genotype (OR=3.4). In contrast, only 1 responder (8.3%) was homozygotes of GSTT1 null genotype. Furthermore, no statistically significant difference in the response rate of the different MDS subgroups was observed. Our results suggest that a treatment with rHuEpo may be effective in achieving a stable erythroid response in MDS patients who carry an homozygous deletion of the GSTM1 gene.

Aged↗
PubMed2003

Distribution and frequency of beta-thalassemia mutations in northwestern and central Greece.

OBJECTIVES: Beta-Thalassemia is a common autosomal recessive disorder resulting from over 200 different mutations of the beta-globin genes. The spectrum of beta-thalassemia mutations in Greece has been previously described in the population of the capital city of Athens, or in beta-thalassemia patients having transfusion therapy. The aim of the present study was to identify the distribution of the most common beta-thalassemia mutations in the population of northwestern and central Greece. METHODS: The data for this study were derived from a total of 1,130 unrelated subjects including 46 beta-thalassemia major, three beta -thalassemia intermedia and 1,081 carriers identified in our antenatal screening program. beta-Thalassemia mutations were identified by ARMS, DGGE and Reverse Dot Blot. RESULTS: The most common mutation, IVS-I-110, is followed, in order of frequency, by the mutations Cd-39, IVS-I-1, IVS-II-1, Cd-6, IVS-I-6, IVS-I-5, IVS-II-745, Cd-5 and 44 bp del. IVS-I-110 and Cd-39 frequencies are similar with those found in other Balkan countries. Significant differences in regional distribution were observed. The results showed a clear drift of the distribution of the most frequent IVS-I-110 mutation in the south-north (29.4, 40.0, 44.6 and 61.7%) and the east-west axis (31.8 and 44.6%). CONCLUSIONS: Population screening and prenatal diagnosis are significantly facilitated by these data. Furthermore, the detailed distribution tables of beta-thalassemia mutations are essential for counseling and extraction of genetic diversity estimates for population genetic studies in other inherited disorders.

DNA Mutational Analysis↗
PubMed2003

The role of ultrasonographically guided puncture of the human rete testis in the therapeutic management of nonobstructive azoospermia.

We attempted to characterize the cells collected from the rete testis via ultrasonographically guided puncture. Unilateral puncture of the rete testis was performed in nine men with obstructive azoospermia and 51 men with nonobstructive azoospermia. All the aspirated samples from the rete testis were observed via confocal scanning laser microscope and some of them after fluorescent in situ hybridization techniques. Then therapeutic testicular biopsy was performed in the punctured testis of each man. Spermatozoa were found in all rete testis samples and all biopsy samples from obstructed men. Twenty-two nonobstructed men demonstrated absence of spermatozoa in biopsy samples. Twenty-nine nonobstructed men showed spermatozoa in biopsy material and 24 of these men (82%) had demonstrated spermatozoa in rete testis samples. There were no significant differences in fertilization and cleavage rate between intracytoplasmic sperm injection trials using biopsy spermatozoa and rete testis spermatozoa both in obstructed and nonobstructed men. Considering that puncture of the rete testis does not reduce the volume of testicular parenchyma, is less invasive and apparently causes less detrimental effect on testicular vasculature than biopsy, puncture of rete testis is recommended as first line approach for the treatment of azoospermic men. If puncture is negative for spermatozoa in nonobstructed men, biopsy is indicated.

Biopsy↗
PubMed2002

Association of oestrogen receptor alpha polymorphisms and androgen receptor CAG trinucleotide repeats with male infertility: a study in 109 Greek infertile men.

This study was performed to examine the contribution of genetic polymorphism of oestrogen and androgen receptor (AR) genes in male infertility. We have studied in total 173 Greek men, 109 infertile patients and 64 controls (group A). Patients were divided in to three subgroups: group B (n=29) with idiopathic moderate oligospermia, group C (n=42) with azoospermia or idiopathic severe oligospermia and group D (n=38) with azoospermia or oligospermia of various known aetiologies. All patients and controls were genotyped for two polymorphisms of the oestrogen receptor alpha (ERalpha) gene and also for the (CAG)n repeat length polymorphism of the X-linked androgen receptor (AR)gene. The control group had statistically significant difference from group C regarding the XbaI polymorphism of ERalpha gene. Despite the fact that we did not observe any statistically significant differences in the mean and range of the CAG repeat number, the frequency of the higher repeats of the nucleotide repeat sequence (CAG)n of the AR gene was 2-4 times higher in groups B and C compared with the control group A. Our results indicate that both ERalpha and AR gene play significant role in male fertility. It is possible that a synergy may exist between unfavourable genotypes of these two genes in male infertility.

Adult↗
PubMed2002

The genetic basis of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age. The disorder is characterized by clinical features of hyperandrogenism, menstrual irregularities and often central obesity and hyperinsulinaemia. PCOS may increase the risk for infertility, type 2 diabetes mellitus, dyslipidaemia, cardiovascular disease and endometrial cancer, emphasizing the need for early diagnosis of the syndrome. The genetic basis of PCOS is unknown. There is a strong familial component but the mode of inheritance is uncertain and several candidate genes have been proposed to contribute to susceptibility. Not only genes involved in steroid hormone biosynthesis have been studied but also genes associated with the regulation of insulin secretion and action since hyperinsulinaemia is a characteristic of PCOS. So far there is evidence that INS VNTR (insulin variable number of tandem repeats) or CYP11alpha (cholesterol side chain cleavage) genes are associated with this syndrome. PCOS appears, however, to be an oligogenic disorder and more studies are necessary to define the genetic basis.

Cholesterol Side-Chain Cleavage Enzyme↗
PubMed2001

Expanded cytological referral criteria for colposcopy in cervical screening: comparison with human papillomavirus testing.

OBJECTIVE: The goal of this study was to investigate whether expanded cytologic referral criteria for colposcopy or the addition of human papillomavirus (HPV) testing on cervical screening could improve the rates of detection of cervical intraepithelial neoplasia (CIN). METHODS: HPV testing by semiquantitative polymerase chain reaction/ELISA was performed in 1000 women who were self-referred for routine Pap smear. They underwent colposcopy following an abnormal smear result or a positive HPV test. As abnormal smear results were considered reports of low- or high-grade squamous intraepithelial lesion, atypical squamous cells of undetermined significance, and even HPV-associated reactive cellular changes (mild koilocytosis, mild dyskeratocytosis, hyperchromatic nuclei, bimultinucleation, and cleared cytoplasm). Loop excision of the transformation zone was performed in women with cytology and colposcopy indicative of CIN, as well as in women with normal cytology but positive HPV test and colposcopic impression of CIN. RESULTS: The Pap test was abnormal in 89% of the cases of CIN 1 (34/38) and 96% of CIN 2/3 (27/28) diagnosed in our population. HPV testing picked up four additional cases of CIN 1 (11%) and one case of CIN 2/3 (4%). Overall the HPV test detected 95% of the cases of CIN 1 (36/38) and 89% of the cases of CIN 2/3 (25/28). CONCLUSION: HPV testing does not appear to add significantly to cytology in terms of positive predictive value or detection rate, if extended cytologic indications for colposcopy are used.

Adolescent↗
PubMed2001

The Sp1 COLIA1 gene polymorphism, and not vitamin D receptor or estrogen receptor gene polymorphisms, determines bone mineral density in postmenopausal Greek women.

Several genetic polymorphisms are implicated as determinants of bone mineral density (BMD) in postmenopausal women. These include the Sp1 polymorphism of the collagen type I alpha 1 (COLIA1) gene, the FokI and BsmI polymorphisms of the vitamin D receptor (VDR) gene, and the PvuII and XbaI polymorphisms of the estrogen receptor (ER) gene. The relative importance and the independence of these genetic effects have not been studied simultaneously in the same population. We evaluated the effects of these polymorphisms on lumbar spine BMD among 154 postmenopausal Greek women. BMD tended to differ across Sp1 genotypes (mean 0.842 g/cm2 in SS, 0.851 g/cm2 in Ss, 0.763 in ss, age-adjusted p = 0.056), mostly because ss homozygotes had lower BMD (p = 0.018 compared with SS and Ss). No other polymorphisms were associated with BMD in this population (p = 0.53 for FokI, p = 0.94 for BsmI, p = 0.80 for PvuII, p = 0.91 for XbaI). In multivariate modeling, the effect of ss homozygosity was clinically and statistically significant (-0.105 g/cm2, p = 0.013) after adjusting for age, weight, height, hormone replacement use, and the other four polymorphisms. None of the other four polymorphisms was retained as an independent predictor of BMD in a backward elimination model and no significant synergistic effects were observed when gene interactions were tested. When all five polymorphisms are considered simultaneously, the Sp1 COLIA1 polymorphism seems to have the most unequivocal effect on BMD, at least in postmenopausal women.

Adult↗
PubMed2001

Preimplantation genetic diagnosis for spinal and bulbar muscular atrophy (SBMA).

X-linked spinal and bulbar muscular atrophy is characterized by adult onset motor neuron disease and results from a defect in the androgen receptor. The disease is caused by a dynamic mutation in the first exon of the androgen receptor gene, involving a CAG trinucleotide repeat. We have developed a single-cell polymerase chain reaction assay for the androgen receptor gene and describe the application of this assay for preimlantation genetic diagnosis (PGD) in a couple at risk, where the female partner is a carrier of 47 repeats. Diagnosis was based on the detection of both normal and expanded alleles. Allele dropout of the expanded allele was observed in only 1 of 25 lymphoblasts of the carrier and of a non-expanded allele in 1 of 20 research blastomeres tested before the actual PGD. One contraction of four repeats was also found in the carrier's lymphoblasts. Neither expansions nor contractions were observed in the blastomeres biopsied from 11 embryos. Two embryos were unaffected, eight were female carriers and one was an affected male embryo.

Alleles↗
PubMed2001

Congenital obstructive azoospermia in a man with Marfan syndrome.

OBJECTIVE: To present a case of Marfan syndrome and concurrent congenital obstructive azoospermia. DESIGN: Case report. SETTING: Tertiary-care academic hospital. PATIENT(S): A man with Marfan syndrome and obstructive azoospermia. INTERVENTION(S): The patient was evaluated for azoospermia that was proved to be due to congenital absence of large segments of vas deferens and epididymis bilaterally. MAIN OUTCOME MEASURE(S): Evaluation for testicular sperm extraction and ICSI procedure. RESULT(S): The patient is a candidate for testicular sperm extraction and ICSI. CONCLUSION(S): The Marfan syndrome and azoospermia may be associated in sporadic cases.

Adult↗
PubMed2001

Novel PKD1 deletions and missense variants in a cohort of Hellenic polycystic kidney disease families.

The autosomal dominant form of polycystic kidney disease is a very frequent genetically heterogeneous inherited condition affecting approximately 1 : 1000 individuals of the Caucasian population. The main symptom is the formation of fluid-filled cysts in the kidneys, which grow progressively in size and number with age, and leading to end-stage renal failure in approximately 50% of patients by age 60. About 85% of cases are caused by mutations in the PKD1 gene on chromosome 16p13.3, which encodes for polycystin-1, a membranous glycoprotein with 4302 amino acids and multiple domains. Mutation detection is still a challenge owing to various sequence characteristics that prevent easy PCR amplification and sequencing. Here we attempted a systematic screening of part of the duplicated region of the gene in a large cohort of 53 Hellenic families with the use of single-strand conformation polymorphism analysis of exons 16-34. Our analysis revealed eight most probably disease causing mutations, five deletions and three single amino acid substitutions, in the REJ domain of the protein. In one family, a 3-bp and an 8-bp deletion in exons 20 and 21 respectively, were co-inherited on the same PKD1 chromosome, causing disease in the mother and three sons. Interestingly we did not find any termination codon defects, so common in the unique part of the PKD1 gene. In the same cohort we identified 11 polymorphic sequence variants, four of which resulted in amino acid variations. This supports the notion that the PKD1 gene may be prone to mutagenesis, justifying the relatively high prevalence of polycystic kidney disease.

Amino Acid Sequence↗